Keep your hands up and protect yourself, Justin Bieber!
The singer was at a boxing gym in El Lay on Friday putting up the mitts and getting a good session in, and as you can see (above), it sure looks like he went all-in on the look AND the workout!!
Then again, based off his recent habits of punching fans in the face, something tells us this is FAR from the Biebs' first time putting up the dukes!!
No word on whether he's ready to fight pal Floyd Mayweather, Jr. next or what, though.
[Image via AKM-GSI.]