Britney and Kevin facing sex tape scandal

A video of Britney Spears and husband Kevin Federline getting nasty is thought to be on sale to the highest bidder.

The tape, said to have been filmed while Britney was still expecting son Sean Preston, was apparently copied by a member of the singer's entourage.

"He has threatened to release raunchy footage of the two taken before Spears looked pregnant," a source told Us Weekly magazine.

According to reports, a copy of the tape viewed by the couple's lawyers elicited both "laughter and disgust".

Meanwhile, eBay bidding on one of Britney's "jewel encrusted" bras - sold to benefit the victims of Hurricane Katrina - passed $33,000 late Thursday afternoon.