Britney & K-Fed Celebrate His Birthday in Vegas

Is Britney Spears pregnant? Spears added fuel to the fire Tuesday night in Las Vegas by partying the night away and never letting a drop of alcohol touch her lips.

Brit and K-Fed, flanked by a phalanx of security, celebrated his 28th birthday by renting out a portion of the VIP section at Pure nightclub at Caesar's Palace. Coincidentally, Jamie-Lynn Sigler ('The Sopranos') had reserved another section of the VIP lounge. FYI -- the two groups never mixed.

Britney was a true teetotaler -- she never drank and never smoked the entire evening. But she did irritate some patrons -- whenever Brit went to the bathroom, security cleared a path and closed off the restroom.

Before going to Pure, the famous couple dined at Tao Restaurant. Robin Leach from AOL Journals has the lowdown on the birthday dinner, from what they ate, to the "little people" who presented K-Fed with his birthday cake. Check out his report.

TMZ