The crazy fun began when the former Baywatch babe and some friends hit the music video shoot for "Gettin' Over You," David Guetta's latest single with Fergie, LMFAO and Chris Willis.
Anderson had jaws dropping when...
"She undressed as soon as she got there," a source tells us. "The hysteria continued as she climbed onto a ladder, wearing only lingerie. She practically brought production to a halt. Everyone on set stopped in awe."
We're told that after the video wrapped, the barely dressed bombshell and her friends headed over to her photographer BFF David LaChapelle's studios. About a dozen partygoers, including fellow DWTS-ers Cheryl Burke and Evan Lysacek and publicist pal Avo Yermagyan, sipped Fortune vodka while Anderson gave a surprise dance performance.
"By the end of the night, Pam was dancing around in nothing but her birthday suit," our spy says. "Everyone was shocked, but everyone was having fun."
Fingers crossed Pammy invites us to her next night out on the town.
Pam isn't the only celeb who likes having a good time. Check out our Party Pics: Hollywood photo gallery.