Recently engaged Fall Out Boy Pete Wentz has been slammed with a lawsuit claiming he assaulted a fan after a gig at the Schuba’s Tavern in his native Chicago, Illinois last year.

Andy Kallas, also of Chicago, has launched legal action against the musician, alleging he suffered “serious injuries to his head, mouth and face” during an unprovoked attack outside the club.

Andy says he was just enjoying the band’s performance when Pete and his posse began beating on him for several minutes. Spywitnesses claim concertgoer Kallas was heckling the band just prior to the fight.

He is suing Wentz and Schuba’s Tavern.

Pete insists his accuser is just out to make an easy buck, calling the lawsuit baseless.

He tells MTV.com: “This lawsuit is entirely without merit and will be vigorously defended.
“This is another in a long line of frivolous lawsuits that are filed against celebrities each year from individuals seeking a quick payoff when there is absolutely no justification for the claim.”
Kallas is reported to have jeered at the band during the gig, but Wentz is adamant he would never lose his temper over something so trivial….We get heckled onstage all the time, and while I’m a jerk, I’m not the kind of person who would ever lash out at someone simply over this.”