According to NowMagazine, mystery man wants to sell Britney Spears’ sex tape video on web.

A man claims he filmed himself having sex with Britney Spears – and plans to sell the tape on the web.

He reportedly hooked up with the troubled star at a bar on Hawaii’s Big Island before heading back to her hotel for a steamy session.

He claims Britney took him to the Four Season’s on the Kona-Kohala coast – where he secretly filmed their raunchy encounter.

But the un-named man says he’s annoyed with his poor performance – and admitted it didn’t last very long.

‘It was just normal sex, we didn’t do anything crazy,’ he tells the Daily Star.

‘It was a little disappointing. It lasted for about 25 minutes and then we passed out.’

The latest allegation could be the final blow for the troubled 25-year-old, who is struggling to coming to terms with losing her two sons.