Two thousand eleven has just started, but it's already shaping up to be a landmark year for many young stars. From Britney to Beyoncé to Sienna, celebrities we've watched grow up through their careers are celebrating their 30th birthdays! Mickey Mouse Club alums and model moms, sexy singers and Oscar contenders, check out just who will be saying hello to their thirties over the next 12 months. Get ready for some huge parties and click through to see some faces that might surprise you!
Image Source: WireImage