Justin Bieber Strips Down for Diddy's Tequila Bash

You can't hold a good party boy down.

And Justin Bieber was in full party mode last night when he showed up at Diddy's Deleon Tequila launch soiree at Vanquish nightclub in Atlanta.

The Biebs partied it up shirtless with Diddy, Diddy's girlfriend, Cassie, Rick Ross, T.I., Jermaine Dupri, Trinidad James, and Wale. Bieber's new girl, Chantal Jeffries, was there, too.

Based on the photographic evidence, the "Baby" singer is the only one who decided to party bare-chested. (Maybe he had just come from a heated skateboarding session?)

Everyone's all smiles in the pics. And in case you’re wondering, the 19-year-old Bieber, fresh off drug-enhanced DUI charges in Florida and a pot-powered plane ride to the Super Bowl, appeared to have nothing more than a water bottle with a peculiar-colored liquid in his hand all night in the photos we’ve seen.