Britney Spears received another kick in the teeth from ex-husband Kevin Federline as he partied with her best fremeny, Paris Hilton, over the weekend.

K-Fed and the jailbird socialite were spotted sharing some intimate moments during a night out at Las Vegas club, Lax, where onlookers say that the pair were virtually “inseparable.”

Eyewitnesses claim that the would-be rapper became so excited when he spied Paris that he repeatedly called out to her and then sidled up to plant a kiss on her cheek.

Then he apparently whispered in her ear, before both of them began giggling.

"It looked as though they were getting quite friendly," one onlooker said.

K-Fed and Paris took on Pure on Sunday night - although the socialite's affections appeared to lie elsewhere. 

To see Paris gettin' down 'n' dirty at Pure, click here!