She usually sports red-hot lipstick, heavy blush and eyeliner, pinup-style curls, and outlandish get-ups (Technicolor jumpers, lingerie, hot pants) only a pop star could get away with.  But on Monday night, Katy Perry was just another girl out on the town.

In a sweater dress and extremely simple makeup, the 25-year old singer had dinner with girlfriends at West Hollywood's Philippe restaurant; barely recognizable, the "Waking Up in Vegas" star blended right in.

Absent from the quiet evening: Perry' s boyfriend, British comic Russell Brand. At MTV's European Music Awards earlier this month, she wore a lingerie ensemble with his nickname, "Rusty" across her derriere.

"I spent a lot of time working out every single detail, just making sure every look was perfect," Perry said of her attention-getting stage outfits.