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Troian Bellisario, Lucy Hale (in Rebecca Minkoff) and Shay Mitchell, the stars of ABC Family’s Pretty Little Liars, teamed up on ‘A Day’ at the 2012 ABC Family Upfront presentation held at the Mandarin Oriental Hotel in New York City. During last night’s episode, the show revealed its notorious mystery character, A. “#PrettyLittleLiars has the BEST fans ever. EVER. So proud to be a part of this amazing family,” Tweeted Mitchell after the game-changing episode. Click through the gallery to see more stars at last night’s hottest events.

Lucy Hale lightened up her dark brown strands for a new highlighted hue. “My hair was like virgin hair; I had very rarely dyed it,” the Pretty Little Liars star told InStyle.com. “I wanted to do something different. My inspiration was Rachel Bilson. Her colorist did my hair, so I was like, ‘I can’t go wrong!’” However, this 22-year-old’s new shade won’t last forever. “I’ll probably go darker around Christmas time,” she confessed.

Plus, see more hair makeovers, transformations, haircuts, and dye-jobs in the gallery.

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— Sharon Clott, with reporting by Lindzi Scharf

Lucy Hale and Nicole Richie looked fresh faced when they attended a preview of Dior Beauty’s Garden Party Spring 2012 collection at Chateau Marmont in Los Angeles, both wearing looks from the label. “It’s nice to enjoy the weather, have a nice lunch and catch up,” Richie said of the afternoon affair. Click through to see Jennifer Lopez, Taylor Swift and more at last night’s hottest parties!