Paris Hilton's boyfriend Doug Reinhardt fought off a man he caught trying to grope the socialite in a Los Angeles nightclub on Monday night.

The pair were partying with actress Jessica Alba and her husband Cash Warren when the drunk clubber made a grab for Hilton's breasts, reports UsMagazine.com.

A witness tells the site, "Doug protected his lady and pushed the guy. That's when all of Doug's boys stepped in and beat the c**p out of the guy. Then Doug had security kick him out of the club."

But, when approached for a comment, Reinhardt's rep denied all knowledge of the incident, insisting, "Doug was not involved in a fight last night."