As Cardi B prepared the release for her new song "WAP,” she checked off all the usual components of her promotional plan, including magazine covers, Instagram posts and a raunchy YouTube video. Then she added one more: OnlyFans, a site where people charge admirers for special access to videos and photos.

OnlyFans is closely associated with adult models. Many of its most popular creators are attractive women who use it to titillate men willing to pay a few extra dollars for a particular image. But Cardi B is part of a small but growing number of more traditional celebrities turning to OnlyFans to make a little extra revenue, raise money for charity or connect with followers in a new way.

In her first material for the site, posted on Aug. 12, Cardi B uploaded a video from behind the scenes of her photo shoot for the cover of Elle magazine. A few weeks later, she shared footage from the making of her "WAP” music video. The post went on to generate a couple thousand likes on OnlyFans and almost $1,000 in tips.