Justin Bieber punched a guy in the face and threw him against a wall after the man grabbed a woman by the throat at a Coachella party, and would not release his grip on her.
Justin and a friend showed up at a party which was throwed by Patrick Schwarzenegger - the eldest son of Arnold Schwarzenegger and Maria Shriver.
Justin was talking to some people after the party - when a guy walked in, spotted a woman and went ballistic.
Sources at the party say he was on drugs - and it looked as if the woman may have been his ex-girlfriend.
The guy suddenly grabbed the woman by the throat and would not release her. Justin and his friend started screaming at the guy to let her go, but he screamed back "Go f*** yourself". At that point, Justin hit the man in the face and pushed him against the wall allowing the woman to free.
The guy was thrown out of the party and a short time later he started chasing an SUV apparently believing Justin was inside.
He was screaming Justin's name as he began hitting the vehicle. We're told cops eventually came and arrested him.