According to a source, the couple were dancing at H-Wood when an intoxicated male clubgoer approached the heiress and tried to touch her cleavage.
"Doug protected his lady and pushed the guy. That's when all of Doug's boys stepped in and beat the crap out of the guy. Then Doug had security kick him out of the club," Us magazine quoted another source as saying.
The incident even shocked fellow club-goers Jessica Alba and Cash Warren, who were dancing alongside Hilton and Reinhardt. "Alba and Cash looked at one another and were like 'wow," said an onlooker.
However, the Hilton and Reinhardt were apparently unaffected by the brawl, as they mingled with Brody Jenner around 1:20 a.m. before calling it a night shortly after 2 a.m. Despite several witnesses, Reinhardt's rep said: "Doug was not involved in a fight last night."