An overeager fan reached out and touched Justin Bieber's face as he was being driven to a show in Barcelona, Spain today.

The Biebs responded by punching the guy in the mouth hard enough to draw blood.

Bieber's violent side has flared up before. He's pushed Desiigner, put a cig out on the arm of Post Malone and this summer he brawled with a pretty big dude in Cleveland.

In this case, Bieb's victim seemed pretty pleased to have been bloodied by pop royalty.