Mandy Moore was so hurt when ex-beau Wilmer Valderrama spoke publicly about their sex life, it threw her into a deep depression, sources say.

Wilmer, one of Hollywood’s most notorious ladies’ men, boasted to Howard Stern last year that he’d taken Mandy’s virginity.

While Mandy recently revealed that she has struggled with depression – and had been blue over her break-up with "Scrubs" star Zach Braff – The ENQUIRER has learned it was bad boy Wilmer’s kiss-and-tell that sent her over the edge.

"Mandy couldn’t believe her ears when she heard the hurtful and tacky comments," said a friend of the pretty 22-year-old actress/singer. "She just wanted to crawl under a table and hide."

To ease her humiliation, Mandy holed up in a rural mountaintop cabin in the remote Catskill mountain region of New York State.

Things are looking up for Mandy now, though. She was recently spotted getting cozy with Nicole Richie‘s ex-fiance, Adam "DJ AM" Goldstein, at the Sundance Film Festival.

And with a new film with Diane Keaton in theaters ("Because I Said So"), pals say Mandy’s moving in a positive direction.