The "Mirror Mirror" star stayed covered up in her demure Valentino gown. Do you think the dress is the perfect balance of sexy and modest, or would you prefer a prom look that shows a little more skin?
Since 2010, Chelsea Dagger (known in real life as Chelsea Aaron) has been SparkLife's sweatiest editor. She's currently working on a how-to-kiss guide for teens, and when she's not conducting smooch-related research on her life-size Joseph Gordon-Levitt cardboard cutout, she's eating pancakes, stocking up on industrial-strength deodorant, and destroying everyone at Harry Potter trivia. (EXPECTO PATRONUM!)