Prom Night star Brittany Snow says she couldn't have beat her nine-year battle with anorexia without the support of actress (and BFF) Sophia Bush.

"Sophia gives really, really good advice," Snow, 22, reveals in the May issue of CosmoGIRL!. "I was going through a difficult time, and she was going through a difficult time figuring out the whole Chad [Michael Murray split] thing.

"We had so many slumber parties where she held my hand [as we worked] through a lot of different things," Snow goes on. "When somebody can be there through something like that, they're a friend forever."

Snow says she decided to make her struggle with anorexia public after two of her friends died from an eating disorder.