Not all celebrity endorsements have been successful on social media. However, our understanding of the effectiveness of luxury brand celebrity endorsement advertising are limited. On the basis of Self-Congruity Theory (Sirgy, 1985), Meaning-Transfer Model (McCracken, 1989), and Match-Up Hypothesis (Kamins, 1990; Kamins & Cupta, 1994), this study investigates whether three components of image congruity (i.e., brand-celebrity, brand-self, celebrity-self) would influence brand attitudes, ad attitudes, and self-brand connection, and subsequently, influence consumer engagement and purchase intentions. This study also tests the moderating role of consumer type (followers vs. unfollowers of the social media brand page) in these relationships. After conducting a series of pretests to select a focal brand and celebrities, responses from 219 US female adults were used to data analysis. The results of structural equation modeling showed that brand-celebrity congruity was positively related to ad attitudes and brand attitudes. Brand-self congruity was positively related to ad attitudes, brand attitudes, and self-brand connection. Self-celebrity congruity was positively related to ad attitudes and self-brand connection but was negatively related to brand attitudes. Ad attitudes were positively related to brand attitudes and engagement intentions but were not related to purchase intentions. Brand attitudes were positively related to engagement intentions and purchase intentions. Self-brand connection was positively related to engagement intentions, and engagement intentions were positively related to purchase intentions. Finally, the results of a multi-group analysis showed that for unfollowers (n=125), ad attitudes were positively related to engagement intentions but brand attitudes were not. On the contrary, for followers (n=94), brand attitudes were positively related to engagement intentions but ad attitudes were not. This study highlights that self-brand connection is the key to cultivating consumer engagement on social media, along with the consumer’s positive attitudes toward the celebrity endorsement ad and the brand per se. If luxury brands wish to interact with their followers and increase their engagement, they need to focus their efforts on improving brand attitudes and self-brand connection through their brand pages. Our findings suggest that celebrity endorsed advertising contributes to creating self-brand relationships (Dwivedi et al., 2016) but it should be considered as a long-term investment.

• Sanga Song(University of Minnesota, USA)
• Hye-Young Kim(University of Minnesota, USA)