The rise of social-media-mediated celebrity culture raises several philosophical concerns. Therefore, it is not uncommon to see, for example, Hollywood actors being placed in the same bracket as YouTube artists and Instagram influencers. The increased perceived ‘connectivity’ afforded by social media allows online celebrities to reach more fans and increases the perceived engagement or intimacy in the fan-celebrity relationship. In this paper I argue that this online relationship, which is beneficial to celebrities (for brand development) and social media companies (in (...) profiting from the high engagement), has the potential to cause harm to both the celebrities as well as their fanbases (and sometimes innocent third parties). Firstly, I argue that celebrities’ attempts to be more intimate or authentic with their fanbase can turn out to be – more often than not – acts of Sartrean bad faith. Celebrities who tend to project a certain self-styled ‘online authenticity’, given the context of social media’s attention economy, can run the risk of treating a fan as a means-to-an-end, rather than an autonomous for-itself. Secondly, I argue that this phenomenon can catalyse real-world harms, by drawing upon network theory and social psychology. I argue that the connectedness of social media, ‘blending into the crowd’, and social media technologies’ ethos of optimising-for-engagement, leads to real harms to human well-being when fans do not engage critically and mindfully with online celebrities. Examples include Trump-esque celebrity politicians trying to drum up populist influence; celebrities feuding online encouraging fans’ conduct of harmful trolling and harassment; and vilification of those who do not subscribe to the same perceived worldview of a celebrity’s fandom. Following my arguments within, I shall outline an online celebrity’s ethical duties in their social media engagement, with emphasis on the duties that celebrity status comes with, particularly in preventing harms that transcend the online into the offline. (shrink)