J.Lo & BF Clubbing It in Hollywood

12/11/2011 6:30 AM PST

Jennifer Lopez & Casper Smart -- Clubbing It in Hollywood

She's not officially divorced, but Jennifer Lopez is living the single life -- hitting up a raging Hollywood nightclub last night with her new boy toy Casper Smart ... TMZ has learned.

The couple stopped by Boulevard 3 -- and sources tell us, J.Lo and Smart partied all night in a private area of the club ... dancing with each other and being very affectionate.

We ran into Smart on his way out -- but he was tight-lipped.