The ad in question showed both RiRi and Chris Brown, with the words, "Would you rather slap Rihanna or punch Chris Brown?"
Snapchat run third-party ads in the app, and they all have to go through an approval process (by Snap) before appearing in the platform. Meaning yes, someone approved this.
Chelsea Clinton has spoken out against the company and the ad on Twitter, saying, "Awful that any company would approve this."
Since seeing the backlash, Snapchat have apologised and pulled the ad down.
The company told Newsbeat the advert was published "in error" and had been removed immediately.
"The advert was reviewed and approved in error, as it violates our advertising guidelines. We immediately removed the ad last weekend, once we became aware."
"We are sorry that this happened," they added.