I think the below attached paper will help you some what for getting an answer to your problem. But not exactly the same topic but you may get some depend ant factors for your research.
Spry, A., Pappu, R., & Bettina Cornwell, T. (2011). Celebrity endorsement, brand credibility and brand equity. European Journal of Marketing, 45(6), 882-909.
Goldsmith, R. E., Lafferty, B. A., & Newell, S. J. (2000). The impact of corporate credibility and celebrity credibility on consumer reaction to advertisements and brands. Journal of Advertising, 29(3), 43-54.
Erdogan, B. Z. (1999). Celebrity endorsement: A literature review. Journal of marketing management, 15(4), 291-314.
Pornpitakpan, C. (2003). Validation of the celebrity endorsers’ credibility scale: Evidence from Asians. Journal of marketing Management, 19(1-2), 179-195.
Ohanian, R. (1990). Construction and validation of a scale to measure celebrity endorsers' perceived expertise, trustworthiness, and attractiveness. Journal of advertising, 39-52.
Wiener, J. L., & Mowen, J. C. (1986). Source credibility: On the independent effects of trust and expertise. Advances in consumer research, 13(1), 306-310.
Start wth http://www.files.honouroverglory.com/COMPUTERS/oldpc/DESKTOP/DISSERTATION/JOURNALS/1.pdf for the chain of effects model from Holbrook and Chaudhri, then extend the model from https://scholar.google.com/citations?view_op=view_citation&hl=en&user=duHgbcQAAAAJ&citation_for_view=duHgbcQAAAAJ:9yKSN-GCB0IC Lafferty and Goldsmith model. This is what I have instructed for a thesis and a conference paper. Very adaptable model. .