Britney Blacks Out While Her Exes Party

“Extra” spotted wild child Britney Spears in New York over the weekend, where she stripped down to lingerie and dirty danced with another nearly naked girl.

While music's biggest superstars rocked the Grammy Awards, Brit unleashed her inner bad girl inside Manhattan's Club One.

When it seemed the pop princess was no longer pleased with her outfit, she did a wardrobe change with one of the barely dressed dancers.

But things apparently got even more out of control at the end of the night: according to multiple sources, Britney was unconscious as she was carried out of the club in the wee hours of the morning.

As Britney let loose in the Big Apple, her exes, Kevin Federline and Justin Timberlake, hit up the party scene in Los Angeles.

JT and K-Fed crossed paths at the Verizon-Rolling Stone bash, where the cameras caught them exchanging a friendly hand shake before going their separate ways.

Click on an image below to see the Britney Spears photo gallery!