Hilary Duff was far from her usual goody-two-shoes self on January 25 when she and older sister Haylie showed up at L.A. club Hyde with a huge entourage.

A Source says that Hilary arrived arm-in-arm with her sis’ a little after 11 p.m., looking tipsy. She was soon was teetering over to the women’s restroom with one of her girlfriends and a “flamboyant” male friend.

“It was kind of inappropriate,” the onlooker sneers. “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 sisters continued to party Paris Hilton-style throughout the night at a VIP table, where our source says they were “all over” their two man-dates. Haylie whispered in the ear of her 30-ish-year-old date while kissing his neck. Hilary perched on her date’s lap, laughing and flirting with her own older man.

Says the source: “When I’ve seen Hilary out in the past, she has been relatively composed, but tonight she was acting pretty wild.”