Justin Bieber hiked Runyon Canyon in Hollywood on Saturday, and when our photographers snapped him on the way down, the 22-year-old pop superstar whipped his t-shirt off and flaunted his tatted up guns -- and abs. Wheeee!

Biebs was in a great mood, and while he wasn't joined by lady love Sofia Richie, we have a feeling he'll be spending the rest of the weekend with her. After all, following their romantic getaway to Cabo last week, they've spent the last few days apart, so they're def due for some couple time. On Friday she was spotted out and about with dad Lionel Richie, and the previous night she went to dinner with a male pal while he hit the clubs.

Of course, it's so much harder to keep track of him now that he's deleted his Instagram account. Can he please get that back up and running? We miss his shirtless selfies and the candid snapshots with Sofia...