Jamie Foxx got into a fistfight at an Usher concert last night in Hollywood … according to eyewitnesses at the show.

Sources inside the concert say Jamie was in an exclusive lounge area near the stage at Avalon — and that the pushing and shoving started just as Usher was hitting the stage.

We’re told the fight started when someone took a pot shot at Jamie … who defended himself and actually got a punch in too before security guards broke up the scrum…

READ MORE ABOUT JAMIE’S SCUFFLE HERE