Britney Spears celebrates Kevin Federline's birthday in Vegas - and drinks!

If you believe the tabloids, Britney Spears’s biggest problem with her husband, Kevin Federline is his partying. And the place Kevin most likes to party is Las Vegas. But the pop star gave in to her hubby for his birthday and celebrated the occasion with him in the town he loves.

Britney and Kevin went to popular Vegas restaurant Tao on March 21 - Kevin’s 28th birthday. They showed up just after 8:30 and met with ten friends in a private room, says People magazine. Britney proved the recent pregnancy rumors wrong by drinking a cosmopolitan with her meal. Kevin, clearly no fan of moderation, drank a Jack and Coke along with shots and beer.

Dinner included sushi, spare ribs, crispy tuna, pork rolls, lobster tempura, Chilean sea bass, chicken satay and grilled Kobe beef, but the real treat was the cake, which, quite “tastefully,�? was served by two female little people. The servers “climbed atop a table to sing him ‘Happy Birthday,’�? reports the New York Daily News.

The group then proceeded to Pure Nightclub where Spears and Federline “didn't leave each other's side all night," a witness told People. After she requested Prince, a barefoot Britney “was doing all her famous dance moves. Toward the end of the night, [she and Kevin] were all over each other – kissing and hugging, having a great time," said the source.

When she wasn’t cutting a rug, Britney who was wearing a black dress with a very low cut back, got cozy with Kevin on Pure's VIP bed and was "draping herself all over [him]," a source told NYDN.

Click here to watch TMZ's video of Britney and Kevin Federline going into Tao