A representative for British pop star Tulisa Contostavlos has hit out at a fraudster offering up a fake sex tape purportedly featuring the singer.

Tulisa has categorically never allowed anyone to film her having sex

A conman is trying to sell the explicit footage for $800,000 , but the N-Dubz star's publicist has dismissed the move as a tactic to make money,because of Contostavlos' new-found fame as a judge on Britain's The X Factor.

And the spokesperson insists the brunette has never been involved in a recorded romp.

The rep tells Britain's The Sun, "This tape is 100 per cent fake and isjust someone trying to cash in on her X Factor role. "She is horrified that someone would go to the extreme lengths of fabricating a video.

It is absolutely not her.

Tulisa has categorically never allowed anyone to film her having sex".