Kevin Federline Parties while Britney Spears in Rehab

Super Dad Kevin Federline spent Saturday night in a Las Vegas nightclub while his estranged wife Britney Spears relaxed at the Promises rehab facility in Malibu, Calif reports Star Magazine.

"Kevin came in at about midnight with about 15 friends to the new club Revolution, and left at 3 a.m.," a source tells Star. The DJ was playing Justin Timberlake's song "Sexy/Back" when Kevin arrived, but then the music switched to oldies. When Bon Jovi’s "You Give Love a Bad Name" came on, Kevin's friends sang to the chorus and pointed at Kevin as he sat there and smiled. "Kevin then looked at the crowd and said, 'Federline's in the house!' and high-fived the DJ," an eyewitness tells Star.

Kevin kept it low key, even playing Tic-Tac-Toe on the interactive light table. "He really just hung out with his immediate group of friends all night, though there were plenty of girls trying to get into the VIP area to meet him," the eyewitness tells Star. "The only girls around him were girls he brought, but they all said they worked for him somehow."

Kevin drank Grey Goose vodka and Jim Beam and ate chicken dishes.

"Later on in the night a girl in a gray dress talked to Kevin for a long time but there was no flirting," adds the eyewitness.

Last week Britney offered Kevin £100,000 to drop a custody hearing over their two sons reports NOTW

Sources say the couple have put their differences behind them and plan to renew their marriage vows as soon as Britney gets out of rehab.

It has been alleged the former pop princess's erratic behavior has been caused by Class A drug crystal methamphetamine.

Crystal meth affects the brain and nervous system, triggering side effects like agitation, paranoia, confusion and violence.

Britney has struggled with drugs before and sources close to the rehab clinic have said she is attending sessions designed to address drug and booze problems.

Pals have claimed that they have seen her taking cocaine and ecstasy in the past.