JENNIFER LOPEZ, CASPER SMART PARTY 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.