Orlando Bloom is the last person I'd think of if someone even mentioned a celebrity bar fight, but evidently he was involved in one. Bloom mixed it up with Justin Bieber early this morning at some popular restaurant in Ibiza, Spain.

Witnesses tell TMZ it started when the Biebz purposely bumped into Orlando. Orlando then went after him and took a swing (and a miss) at him. According to the gossip site, Justin ducked, then yelled, "What's up, [B-word]?" A brief puffing of the chests by the door followed before Bieber left . . . and the crowd applauded.

Here's some video for your viewing pleasure. In the first, you can see Bloom deliver a shove to Justin's face ...

The second video catches the action afterwards ...

And how's this for a b***h move: last night at about 9:40 our time, Justin posted this photo of Miranda before quickly deleting it.

The bad blood dates back to 2012 after Justin and Miranda Kerr hung out backstage at the Victoria's Secret Fashion Show while she and Bloom were still very married (There were rumors they did more than just hang out ... if you know what I mean, and I think you do). Then earlier this year, Orlando was spotted with Biebs ex, Selena Gomez a few different times.