THE ROLE OF BRAND ATTITUDE AND BRAND CREDIBILITY AS A MEDIATOR OF THE CELEBRITY ENDORSEMENT STRATEGY TO GENERATE PURCHASE INTENTION

: The growth of Instagram continues, with the majority of its users being millennial consumers who share all aspects of their life on social media. One of the most popular advertising strategies is using celebrity endorsers. The purpose of this study is to investigate the role of brand attitude and brand credibility as a mediator of the celebrity endorsement to purchase intention. This study can be categorized as explanatory research and the sampling technique used in this research is purposive sampling. The result of this study showed that celebrity endorsement would not directly affect purchase intention, though celebrity endorsement can enhance brand attitude and brand credibility which in turn increase purchase intention.This study only focused on apparel products. Thus future research may consider using another type of product. Further, future research is expected to use another social media other than Instagram and to consider using another variable as the mediator.

During the past decade, people around the world has experienced a rapid change in relation with technology, especially the use of smartphones (Chun,et al., 2012 andKim,et al., 2014).In comparison with traditional phone, a smartphone has many advantages, for instance, the ability to access internet content and social media (Jung, 2014 andHa,et al.,2015).Instagram is one of the fastest growing social media with 700 million active users around the world as of July 2017.
Instagram is an application which enables users to share their life images with others, and it can be the source of electronic word of mouth (eWOM) (Cheung and Lee, 2012).eWOM has become a persuasive information source due to the emerging popularity of social media.The higher the number of followers a person has, the higher the social influence they have (Jin and Phua, 2014).This phenomenon causes the formation of a term of Instagram Famous, or it is better known as Instafamous.
Instafamous' profile is at the top of the list of the most followed pages on Instagram because of

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The Role of Brand Attitude and Brand Credibility As a Mediator they due to the attractiveness of the photos or videos they shared.Instafamous are considered the credible source in generating positive eWOM regarding particular products and services.This phenomenon is widely used by marketers around the world as one of the promotion tools to increase their sales.
Promotions are one of the elements of marketing mix which refers to the entire set of activities, which goal is to communicate the product or the brand to the user.The idea of the promotion is to make people attracted to buy the product over others (Tjiptono, 2008).Celebrity endorsement is a popular method for improving the advertisements' effectiveness.The use of celebrity endorsement has become a trend and a perceived winning formula to build corporate image and to increase sales.Celebrity endorser is defined as any individual who enjoys public recognition and who uses the recognition on behalf of a consumer good to promote the product (Kim andNa, 2007 andSpry, et al., 2011).
The efficacy of the message communicated by an endorser would depend on the endorser's attractiveness, expertise, and trustworthiness as perceived by the consumers (Ohanian, 1991).Attractiveness is related to how physically attractive the source is to the audience endorser (Amos,et al., 2008 andMagnini,et al., 2010).Erdogan, et al. (2001), defines trustworthiness as the degree of confidence in the communicator's intent to communicate the assertions he/she considers the most valid.Expertise, on the other hand, is the extent to which a communicator is perceived to be a source of valid assertions (Amos,et al., 2008).
Celebrity endorsement is widely perceived to bring many benefits, one of which is the increase of purchase intention (Gupta, et al., 2015, Malik and Qureshi, 2016, and Suki, 2016).Purchase intention is an important factor that must be considered in relation to increasing sales because purchase intention depicts the impression of consumer retention.Nevertheless, some researches come to the conclusion that celebrity endorsement is not significantly affected purchase intention ( Carvalho, 2012, Gupta, 2015,and Hassan, 2014).Thus, the research gap in this research arises due to the inconsisten-cies from previous research results regarding the effect of endorsement strategies on purchase intention.
Selection of brand attitude as a mediator in this study is because celebrity endorser can favorably affect consumer 's attitude towards the brand (Solomon, 1994).In addition to brand attitude, this research also puts brand credibility as a mediator.It is based on The Transfer Meaning Model which states that the credibility of the endorser will be transferred to the brand so that the higher endorser's credibility perceived by the consumer, the higher credibility a brand possesses.
This research was conducted on Vanilla Hijab account in Instagram (@vanillahijab).Vanilla Hijab is one of the largest online shops on Instagram with the number of followers more than 800 thousand accounts as of November 2017.Moreover, Vanilla Hijab is well known of the usage of their celebrity endorsement strategy.This study attempts to verify whether celebrity endorsement can increase consumer's purchase intention.

LITERATURE REVIEW CELEBRITY ENDORSEMENT
Celebrity endorsement is frequently used in advertisements on the premise that endorsers play an important role in persuasive communications.In this regard, marketing and advertising practitioners use celebrity endorsement as a promotional strategy in launching new products, repositioning brands or reinforcing brand images (Erdogan, et al, 2001 andOhanian, 1991).A celebrity endorser may be defined as "an individual who uses public recognition to recommend a product in an ad" (Belch, 2004).The efficacy of the message communicated by an endorser would depend on the endorser's attractiveness, expertise, and trustworthiness as perceived by the consumers (Ohanian, 1991).
Attractiveness is related to how physically attractive the source is to the audience (Ohanian, 1991).Attractive endorsers are perceived to be more positive to reflect the endorsed brands (Mowen and Mowen, 2002).The effectiveness of an advertisement with attractive endorser will be higher than an advertisement with a less attractive endorser.Consumers tend to form positive stereotypes about such people and, in addition, research has shown physically attractive communicators are more successful at changing beliefs (Ohanian, 1999).
Trustworthiness refers to the degree of honesty, integrity and believability of an endorser perceived by consumers (Erdogan, 1999 andErdogan,et al., 2001).Advertisers capitalize on the value of trustworthiness by selecting endorsers who are widely regarded as honest, believable, and dependable.Atkin and Block (1983),argues that consumers view untrustworthy celebrity endorsers, regardless of their other qualities, as questionable message sources.Improving the trustworthiness aspect of an endorser is the most effective way of increasing consumers' confidence towards the brand (Suki, 2016).
Expertise is defined as the extent to which a communicator is perceived to be a valid source of assertions (Amos,et al., 2008 andMagnini,et al., 2010).It refers to the knowledge, experience or skills possessed by an endorser.Expert sources influence perceptions of the product's quality.A source/celebrity that is more expert has been found to be more persuasive and to generate more intentions to buy the brand (Ohanian, 1991).

Brand Attitude
Attitude towards a brand is related to the consumers' preference and overall evaluation of a brand, which depicts their likes and dislikes (Solomon, 2014).Brand attitude is thought to be a marker of behavioral intentions.The attitude towards the brand has a significant effect on its purchase intention since brand attitude is the most important determinant of purchase intention.Considering the Theory of Reasoned Action (TRA), Till and Busler (2000), observed that attitude toward performing the behavior is one of the significant predictors of purchase intention.The study further showed that purchase intention is high if a consumers' attitude towards the brand is favorable (Till and Busler, 2000).Till and Busler (2000), argues that the higher the consumer's attitude toward a particular product or brand, the greater the effect on their behavior regardless of the direction of his influence.Attitude toward the brand is an enduring evaluation that presumably energizes behavior (Spears and Singh, 2004).A lot of studies have examined the influence of celebrity endorsement on product or brand (McCracken, 1989 andTill andBusler, 2000), and have shown that celebrity endorsement can create an impact on a product and brand attributes.

Brand Credibility
Credibility is widely defined as the believability of an entity's intentions at a particular time.Thus, brand credibility is defined as the believability of the information contained in a brand, that consumers perceive that the brand has the ability (expertise) and willingness (trustworthiness) to continuously deliver what has been promised (Erdem and Swait, 2004).Brand credibility has a great impact during a brand consideration process (Erdem and Swait, 2004).Brand credibility also encompasses a company's reputation which is considered an important factor to achieve success (Newell,et al., 2008).
Prior research shows that brand credibility not only impacts consumers' brand choice (Erdem and Swait, 2004), but also increases consumer's purchase intention (Daneshvary and Schwer, 2000).Moreover, it is proposed that the credibility of an endorser will be transferred to the brand.Therefore, a firm can work towards building brand credibility as it is largely driven by the quality of the information conveyed through the marketing strategies.

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The Role of Brand Attitude and Brand Credibility As a Mediator

Purchase Intention
Purchase intention is the implied promise to one's self to buy the product again whenever one makes the next trip to the market (Kudeshia and Kumar, 2017).It has substantial importance because the companies want to increase the sale of the specific product for the purpose to maximize their profit.Purchase intention depicts the impression of customer retention.
Jin and Kang ( 2011), explains purchase intention is related to four behaviors including the undoubted plan to buy the product, thinking unequivocally to purchase the product, when someone contemplates to buy the product in the future and to buy the specific product utterly.Halim and Hamed (2005), explain the phenomenon of purchase intention as the projected behavior of consumers on short basis about the repetition purchase of specific product when someone decided to buy the product whenever they come again to the market.

CONCEPTUAL FRAMEWORK AND HY-POTHESIS DEVELOPMENT
A conceptual framework was built, which is presented in Figure.

METHOD
This study is considered as explanatory research.The population in this study is all consumers of Vanilla Hijab (@vanillahijab), and this research is using purposive sampling technique.Follows are the criteria used in this study to choose the respondents which come under the target population: 1. Women aged between 20 -35 years 2. Has an Instagram account and is a follower of Vanilla Hijab.

Has purchased Vanilla Hijab at least 1x
The required sample in this research is 110 (11 indicators x 10 = 110 respondents), but the researcher adds 30% spare to 143 respondents, and it is rounded up to 150 respondents.The data is analyzed with Partial Least Square method using smartPLS 3.0.

OPERATIONAL DEFINITION OF THE VARIABLES Celebrity Endorsement
Endorser's credibility is measured by 3 (three) indicators referring to Ohanian (1990), as follows: 1. Attractiveness refers to the physical attractiveness of a person 2. Trustworthiness refers to the degree of honesty, integrity, and believability of an endorser perceived by consumers 3. Expertise refers to which extent communicator is perceived to be a valid source of assertions

Brand Attitude
Brand Attitude is measured by 3 (three) indicators referring to Abzari, et al., (2014), Suki, (2016), and Kudeshia and Kumar, (2017), as follows: 1.The extent to which consumers can remember a brand 2. The consumer's preference for the brand 3.The consumer's choice of brands, whether consumers prefer brand comparative to another

Brand Credibility
Indicators of brand credibility are adopted from Erdem and Swait ( 2004), as follows: 1. Expertise is the brand's reputation perceived by consumers 2. Trustworthiness is the level of consumers' confidence that he is willing to deliver what has been promised continuously.

Purchase Intention
Purchase intention is measured by 3 (three) indicators referring to Barber, et al., (2012), Kudeshia and Kumar, (2017), Peng andGo, (2015), andWang, et al., (2013) as follows: 1. Transactional interest, namely the tendency of someone to buy the product.2. The referential interest that is a person's tendency to refer a product to others.3. The preferential interest that is interest that describes the behavior of someone who has a primary preference for the product.

RESULTS AND DISCUSSIONS
The results of each path obtained from the smart PLS 3.0 are as follows: Hypothesis 1, which predicted a positive relationship between celebrity endorsement and purchase intention was found to be non-significant.This empirical result is in line with previous literature (Carvalho, 2012, Jamil dan Hassan, 2014, and Gupta, et al., 2015).The findings for H1 lends support for advertising literature especially with regard to the celebrity endorsement in advertising that convincingly argues the significance of having a credible celebrity in creating a purchase intention.
As suggested by Lafferty and Goldsmith (1999), the reason why purchase intentions were not significant for endorser credibility is that the respondents may be more likely to purchase a product based on the product's specific attributes that are quality, material, etc. rather than relying on the endorser.Moreover, when a celebrity endorses multiple products, it negatively impacts the consumer's purchase intentions, and consumers would be unwilling to buy such products (Malik dan Qureshi, 2016).It is aligned with the fact that Vanilla Hijab endorsers also endorses similar products.For example Hamidah Rachmayanti endorsers various other brands such as NHS, L Beauty by Laudya Cynthia Bella, and so on.Indah Nada Puspita which also became the endorser of another hijab brand -Hijup, HijabChic, and NadaPuspita Scarf.
Hypothesis 2 which predicted a positive relationship between celebrity endorsement and attitude toward the brand was supported.This empirical result is in line with previous literature which stated that the celebrity who is perceived to be credible should be chosen to represent the brand as the credibility plays an important role to escalate the attitude towards the advertisement, the brand and purchase intentions (Lafferty and Goldsmith, 1999, Lafferty, et al., 2002, Roy, et al., 2013,and Wang,et al., 2017).
Consumers' perception of endorser credibility is the main antecedents of brand attitude (Spears and Singh, 2004).Thus it can be concluded that consumers' perception of the endorser's credibility is the main reason for the positive brand attitude.The more positive the consumer's perception of an endorser, then the consumer's attitude toward the brand (brand attitude) will become more positive, and vice versa.
A review on social media (Instagram) about a brand can affect consumers' evaluation of products and brands.Wu and Wang (2011), argue that review from sources with high credibility will lead to a more positive brand attitude than the reviews submitted by sources with low credibility.The result of descriptive statistic shows that Vanilla Hijab endorser has high credibility.It shows that consumers consider the Vanilla Hijab endorser as a credible communicator in conveying brand information, thereby creating a positive brand attitude.
Hypothesis 3 which postulated a positive relationship between attitude toward the brand and purchase intention was found to be significant.This result confirmed some previous research which states that consumers who have a positive brand attitude will have a higher willingness to buy a product (Jin and Gu Suh, 2005, Leonidou, Leonidou and Kvasova, 2010, Sallam and Wahid, 2012, Punyatoya, 2015, Mohd Suki, 2016, and Taute,et al., 2017).Moreover, the result gives support to The Theory of Reasoned Action which proclaims that attitude has a positive influence on the behavioral intention (Ajzen dan Fishbein, 1980).Furthermore, The Theory of Reasoned Action explains that person's attitude towards a product/brand can be associated with their interest towards the brand/products.
Hypothesis 4 which hypothesized a positive relationship between celebrity endorsement and brand credibility was supported.This result of this study gives support to The Meaning Transfer Model which states that the credibility of the endorser will be transferred to the brand (McCracken, 1989).The reason why marketers use celebrities to endorse their products is the view that consumers will consume the image of celebrities and thus consumers will be expected to consume the products associated with the celebrity (Batra andHomer, 2004 andPeetz, et al., 2004).In this case, the results of this research prove that the credibility of the endorser will be transferred to the brand, thus the higher the credibility of the endorser, the higher the credibility of the brand perceived by consumers.SEPTEMBER 2018 Deandra Vidyanata, Sunaryo, Djumilah Hadiwidjojo Hypothesis 5 which proposed a positive relationship between brand credibility and purchase intention was supported.Brand credibility plays an important role in increasing consumer purchase intention.Brand credibility is related to consumers' confidence in the product and the information regarding the capabilities and qualities that have been promised by the brand.Credibility also represents the company's reputation (Newell, et al., 2008).
This study indicates that brand credibility has a significant positive effect on purchase intention.This result is in line with some previous studies (Erdem and Swait, 2004, Wang and Yang, 2010, and Li, Wang and Yang, 2011) which concluded that brand credibility could increase the possibility of consumers to buy a brand.In addition, the results of hypothesis testing show that brand credibility is important in increasing consumers' purchase intention.It can be considered by the company as a suggestion to develop a strategy that can increase consumer preferences for the brand.
Hypothesis 6 which predicted that the brand attitude would mediate the relationship between celebrity endorsement and purchase intention was supported.Further, the result indicates that brand attitude fully mediates the relationship between celebrity endorsement and purchase intention, which means without a positive attitude towards the brand, celebrity endorsement strategy will not be able to generate consumers' purchase intention.This result makes sense because, without a positive attitude towards a brand, purchase intention will not be formed.Consumers' online purchase intention is not only affected by perceived ease of use but also influenced by consumers' attitude towards the brand (Elwada, 2016).
The use of celebrity endorsements will not be able to directly generate in purchase intention, but high credibility endorser can form consumers' positive attitude towards the brand, this will ultimately generate consumers' purchase intention.Accordingly, Vanilla Hijab endorsers are perceived as credible sources to generate consumers' positive attitude towards the brand.For instance, Indah Pada Puspita's lifestyle which is perceived can represent the brand very well, can generate a positive attitude from consumers.
Hypothesis 7 which proposed that brand credibility would mediate the relationship between celebrity endorsement and purchase intention was also supported.Further, the result indicates that brand credibility fully mediates the relationship between celebrity endorsement and purchase intention, which means without brand credibility, celebrity endorser will not be able to generate consumers' purchase intention.
Although online shopping is more preferable in this globalization era because it is considered to offer some conveniences for consumers, online shopping also possesses some risks.The risks are usually related to the number of frauds that often occur while doing online shopping.It makes consumers tend to first consider the credibility of a brand before deciding to do online transactions.In the context of online shopping, the brand credibility is built by providing a quick and friendly response, on time delivery service, delivery of goods in accordance with the consumers' order and the ease of accessing the site.Even though celebrity endorsement cannot directly generate purchase intention, but the credibility of endorsers' perceived by consumers can be transferred to the brand, and thus generate purchase intention.

CONCLUSIONS AND RECOMMENDA-TIONS Conclusion
This study demonstr ates how celebrity endorser's credibility affects brand attitude, brand credibility, and purchase intention.While recognizing the importance of celebrity endorsement on generating purchase intention, the results of this study have important implications for any company, especially online shops in terms of how to adopt celebrity endorsement strategy to maintain customers' intention to purchase the products.
Celebrity endorsement is proved can not generate purchase intention directly.Therefore, once consumers think endorser of the brand is more credible (attractive, trustworthy, and expert).Their atti- The Role of Brand Attitude and Brand Credibility As a Mediator tude towards the endorsed brand will become more positive.Consumers' perception of a celebrity endorser is an important antecedent of brand attitude.Further, a credible source of information can increase the brand credibility as perceived by consumers.It means once consumers think celebrities are credible, consumers' attitude toward the endorsed brand would be more positive.Thus, the celebrity endorsement strategy will be generating purchase intention indirectly through brand attitude and brand credibility.

Recommendation
This study only focused on apparel products.Thus future research may consider using another type of product.Further, future research is expected to use other social media other than Instagram and to consider using another variable than brand attitude and brand credibility.
For the managerial implications, the selection of endorsers should be adjusted with the products characteristic, because endorsers represent the product well can improve brand attitude and brand credibility, and thus will generate purchase intention.Besides, the company should pay more attention to the importance of brand attitude and brand credibility, because without brand attitude and brand credibility, the celebrity endorsement strategy will not be able to generate purchase intention.
1.It is designed to clearly understand the relationship between independent variables to the dependent variable of the study.Based on the conceptual framework, the following seven hypotheses were formulated for this study: H1.Celebrity Endorsement has a positive influence on Purchase Intention H2.Celebrity Endorsement has a positive influence on Brand Attitude H3. Brand Attitude significantly has a positive influence on Purchase Intention H4.Celebrity Endorsement has a positive influence on Brand Credibility H5. Brand Credibility has a positive influence on Purchase Intention H6. Brand Attitude mediates the impact of Celebrity Endorsement towards Purchase Intention H7. Brand Credibility mediates the impacts of Celebrity Endorsement towards Purchase Intention.