04/25/2007 AT 03:00 PM EDT
It was a "Midsummer Night's Dream" bash at the Playboy Mansion, and Paris Hilton
got festive for the party, removing her robe and walking around in sexy black lingerie. The heiress made the rounds with sister Nicky Hilton
and also made sure to say hello to the party's host, Hugh Hefner.
After their chat, the Hilton sisters hit the dancefloor, which was crawling with celebrity guests, including former O.C.
costars Adam Brody
and Benjamin McKenzie
. Despite being quite social, though, Hilton kept her distance from one guest – Shanna Moakler.
"They really just did their own thing," a party guest tells us. More chatty, rocker Dave Navarro
walked around introducing guests to his girlfriend Nicole Bennett.
Says the guest: "They were very cutesy and cozy."