Hilton, 19, and Todd Meister, 33, a money manager from New York, were married at 2:30 a.m. Sunday at the Las Vegas Wedding Bureau in a ceremony being compared to Britney Spears' quickie wedding last January, the New York Post reported Monday.
Hilton and Meister, who reportedly have dated sporadically for more than a year, were in Las Vegas with a number of friends, including Paris, actresses Lindsay Lohan, Bijou Phillips and Tara Reid and Rod Stewart's daughter, Kim, and their respective dates.
The party began at Las Vegas' trendy Palms Hotel and Casino Resort, where they ate sushi and were "just having a really good time," said George Maloof, resort owner.
"I don't think anybody expected this," Maloof said of the wedding, which reportedly was attended by Paris Hilton and Phillips.
Part of the weekend festivities were filmed for "Entertainment Tonight Insider," but the TV production did not get footage of the wedding.