Bieber's back! After a hiatus from showing off his sexy, Justin put his bod on full display at an unusual venue today -- UCLA! To many college girls' (and boys') delight, Biebs broke into the university for a soccer session with a coach and he didn't disappoint his fans -- and he even made some new ones ...

Justin was made a pit stop in Beverly Hills to pick up some new Nike cleats and then headed to Bruins' territory for a soccer workout. A 7-foot metal gate didn't stop him; Justin jumped right over it and started kicking around. Eventually he got too HOT so he took off his BAPE camp sweatshirt and put his new tat on full display. Meanwhile, students started gathering around the field; girls were texting and calling their friends; more and more people showed up and Justin put on a show-stopping performance. He flexed, showed off his footwork -- he's friends with Neymar, remember -- and kicked a few goals.

Selena's one lucky lady ...