Who could forget the look on Heidi Montag's face when her mother gasped at her radical body transformation? Or Mel Gibson's threatening voicemails to estranged wife Oksana Grigorieva? Or Mariah Carey's not-so-secret pregnancy?

Us Weekly Deputy News Editor Natalie Thomas and Senior Editors Ian Drew and Bradley Jacobs look back on the biggest star stories in 2010 -- including Hollywood's most surprising engagement, the year's biggest party foul and more!