Scammers are using AI-generated videos of celebrities including Taylor Swift and Rihanna to promote shady services on TikTok, according to authentication company Copyleaks.

The ads typically show celebrities in interview settings, such as red carpets, podcasts, or talk shows, and often manipulate real footage with AI, the company said. Many promote rewards programs claiming users can earn money by watching TikTok content and giving feedback. TikTok’s official branding appears in some of the ads, though users are redirected to third-party services that ask for personal information.

In one ad, a realistic AI avatar of Swift urges users to sign up to a feature called TikTok Pay. In another, a fake Rihanna says “you literally just watch content and give your opinion.”

It’s another example of how social platforms are struggling to keep up with a surge of convincing deepfakes, which are becoming a messy, everyday problem for users. TikTok is far from alone here. Reports suggest users of Meta’s platforms including Instagram and Facebook see billions of scam ads a day, and the company’s own oversight board has acknowledged it has a deepfake problem. YouTube also says it is “investing heavily” in combating celebrity scam ads.

Celebrities are also searching for new ways to fight back: last week Swift filed new trademark applications for clips of her voice in an attempt to protect herself from AI copycats.