The relationship between celebrities’ credibility and advertising effectiveness
Authors: Hassan Fathelrahman Mansour Ilham , Mohammed Elzubier Diab Dalia 
Published: June 2016

Purpose
The purpose of this study is twofold, first, the study aimed at investigating the impact of celebrities’ credibility on advertising effectiveness by examining the celebrity attributes that are likely to influence consumer attitude towards celebrity-endorsed TV advertising and their purchase behaviour. Second, the study seeks to identify the mediating role of religiosity on consumers’ attitudes towards celebrity-endorsed television advertising and buying behaviour.

Design/methodology/approach
The study is based on a survey questionnaire in a sample of 370 Sudanese customers on their attitude towards the celebrity endorsement of television advertising.

Findings
The study found that celebrities’ likeability and their attractiveness have the greatest impact on both consumers Attitude and their purchase behaviour. The study also confirms that religiosity partially mediate both the relationships between celebrities’ credibility and the attitude towards the advertisement and purchase behaviour and revealed that religiosity correlates negatively with celebrities’ credibility and attitude towards advertisement.

Research limitations/implications
However, the study has some limitations, as it investigates the effectiveness of celebrities’ endorsement in TV commercials only. Future research could be extended to investigate the effectiveness of using celebrities advertising on other different media such as radio, printed and outdoors media. Further, the study uses a scale based on the Islamic practice dimensions, and using a more comprehensive scale to measure religiosity based on both belief and practices may be a further extension.

Practical implications
These results have important implications for advertising practitioners and business enterprises in Sudan, and other similar communities. They provide guidance in the sense that religiosity should be weighed in and given high importance when using celebrities in advertising campaigns and that the advertisement contents should be compliant with the Islamic law (Shariah).

Social implications
Understanding how religious beliefs influence the attitude towards the advertising is of great importance to international advertisers to improve advertising effectiveness without offending their Muslim audience. The study enriches the literature on the religiosity and its influence on the consumer behaviour, particularly in the celebrity-endorsed advertisements.

Originality/value
To the best of the authors knowledge, this study is the first study of its kind in Sudan to explore the impact of celebrities’ endorsement on consumers attitude and buying behaviour and provide empirical evidence to verify the existence of a mediating role of religiosity on both the attitude and purchase behaviour in the Sudanese context. It provides an understanding of Sudanese attitudes and purchase decision, as Muslims, and thus provides practitioners with guidelines on how to design celebrity-endorsed TV advertisements to influence consumers’ attitude and buying behaviour.