Pop superstar Rihanna has slammed reports she's the star of a new sex tape.

The Umbrella hitmaker was alleged to have appeared in a steamy video, obtained by adult company Hustler, alongside rapper J. Cole, who opened for the Bajan beauty on her recent Loud tour.

A representative for Hustler told E! News, "We have not made any decisions about what we are going to do with it yet."

But Rihanna has moved swiftly to deny the gossip, telling her Twitter.com fans, "We don't believe U, U need more people... AND of course an actual sex tape! Slownewsday."