Lauren Conrad isn’t too lucky when it comes to selecting female friends. The Hills spies claim Audrina plays the perfect BFF when cameras are rolling, but when the last frame falls, the brunette goes after the blonde fashion maven with a tongue laced with a razor!

“Audrina is a backstabber!” a source tells Star Magazine.

“She says the meanest things about Lauren, and no one knows why, because Lauren took Audrian under her wing and made her a star.”

Audrina spent Thanksgiving Weekend 2007 telling friends that L.C is ‘crazy, insecure, jealous, and totally fake.’

“Audrina wasn’t editing herself, she just let it all out! She should be more careful who she’s talking to. Lauren has a lot of friends who don’t like to hear this stuff.”