E!: 27-year-old Jasmine Waltz allegedly caught (Lohan) canoodling with her ex, Danny Cipriani.
"There was an altercation between Lindsay and Jasmine at Doug Reinhardt's table over Jasmine's ex Danny," the source said. "Danny and Lindsay have been dating and Jasmine was obviously upset about it."
While Lohan was there to celebrate her 24th birthday, our source said she arrived "relatively solo," didn't have her own table, and instead mingled with other celebs at the club.
Perhaps she should've skipped Reinhardt's table, however, since that was where the drama began.
Lohan, according to our source, didn't instigate the altercation.
"Lindsay was visibly rattled after the incident," the source said. "It's kind of sad because Lindsay didn't really have any friends with her. No firing has been made yet but I think Jasmine probably knew when she threw the punch that that was her last involvement with Voyeur."
A rep for Voyeur would not comment on the incident but confirmed to E! News that Lohan did indeed celebrate her birthday there Thursday night.