Though underage, Hilary appeared drunk to the spy, who ran into her in the bathroom. She had brought a "flamboyant" male pal along with her, says the source, who tattled, "It was kind of inappropriate. She was pretty drunk and staggering around the bathroom, bumping into people and shrieking that her gay male friend had a vagina so it was okay for him to be there."

The show didn't end in the bathroom. Hilary continued her antics at the VIP table with her sister and their dates. Us says Hilary spent a good portion of the night sitting on her fella's lap, openly flirting. Haylie, meanwhile, kissed her date's neck and whispered into his ear. The source says the girls were "all over" the guys. Looks like Hilary has gotten over her ex, Joel Madden pretty quickly.