Justin Bieber Arm Wrestles Shirtless -- Watch!


Justin Bieber has been hitting the gym!

The 23-year-old singer took to Instagram on Saturday to show off his late-night activities: shirtless arm wrestling!

WATCH: Justin Bieber Dodges Hurled Water Bottle After Refusing to Sing 'Despacito' in Concert

The Biebs also gave fans a close up of his game face with a few silly selfies.

RELATED: Luis Fonsi Says Justin Bieber Deserves a 'Pass' for Not Knowing the Lyrics to ‘Despacito’

On Friday, Beiber debuted a new tattoo, reflecting on his past mistakes and explaining that he wants to "work everyday to be BETTER AT 70."

See more in the video below.