The singer, 20, decided to pound the pavement in shiny, leather-look shorts.
Justin pulled his shorts down low, which meant that his posterior was hanging out for the short sprint around the block.
He also kept his phone in his hand, at one point even having a chat while he ran, and he wore a very expensive looking gold watch for the run.
Erm… Sure thing, Biebs!
The Canadian star teamed his unusual running shorts with a pair of neon green trainers and a white vest.
Justin had been driven to Santa Monica Boulevard, hopping out of his car before running along the pavement with a pal.
He said online: "lmao me and @theworldshero running in Hollywood."
Justin has been ramping up his workouts of late and can regularly be found boasting about his super buff body.
So we reckon this short, sharp burst of cardio must be part of his new regime.
On Friday, he shared a video of himself dancing around in the gym and said: "Procrastinating in the gym haha."
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