It's Official -- Justin's Sexy Is Back!

So here's the inside scoop on Justin's Friday night in Vegas ... While partying at Jet after his concert, he got his groove on with ex-girlfriend Alyssa Milano and chatted with newly-engaged Eva Longoria. But here's the kicker -- as the DJ at the party played SexyBack, he suddenly mixed it into "Toxic!" Everyone laughed, including Justin -- lucky for the DJ Justin was in a good mood!

Oh, and I thought I'd throw in this quick clip of the Mansion at MGM (thanks Anon) where Justin spent some time while he was in Vegas -- not bad!