K-Fed, Paris Hilton Party in Las Vegas

An unlikely and trashy duo - Kevin Federline and Paris Hilton - caused heads to turn in Las Vegas over the weekend, partying like rock stars!

Sunday, the duo partied together in Sin City - K-Fed's home away from home - for the second night running. And, of course, getting paid for it.

Both celebrities are in town to host separate New Year's Eve parties - hers at LAX, his at Tangerine - but each big-name attraction started celebrating a few days early, hitting LAX on Saturday and Pure Nightclub on Sunday.

Both K-Fed and Paris have seen Britney Spears, no underwear style.

A source close to Kevin Federline said that the two hung out in Paris Hilton's hotel room Saturday after leaving the club. So it appears the ex-husband of Britney Spears may or may not have become the 200th person to tap that.

Still, Federline and Paris seemed a bit less chummy on Sunday at Pure, mingling only briefly before drinking a shot of tequila together and parting ways.