In this article, I analyse how a celebrity can perform cultural critique and feminist activism using her Instagram account and online book club. The celebrity in question is British film star Emma Watson, famous for playing Hermione Granger in the Harry Potter franchise. Watson is performing her activism on gender equality and cultural critique by recommending feminist literature. This study undertakes an analysis of Watson’s presentations of self on Instagram and in her letters in the Our Shared Shelf book club. The analysis takes its point of departure from theories of social media and celebrity culture and film studies as well as investigations of celebrity book clubs and celebrity activism. This case study of Emma Watson’s performance of cultural critique and activism on specific media platforms demonstrates that Watson’s authority is based on her star image as well as the fact that her book club letters and Instagram posts mutually reinforce one another’s written personal arguments and visual documentation.