Zac Efron
Age: 24
What He's Done: Skyrocketed to fame as Troy in 'High School Musical'; also sang and danced through 'Hairspray'; starred in the somber 'Charlie St. Cloud.'
What's Next: There will be no shortage of Efron action in 2012. The heartthrob has six projects coming up, including 'The Lucky One,' in which he plays a buzz-cut Marine. He'll also be making an appearance in the star-studded 'New Year's Eve' alongside Ashton Kutcher and Robert De Niro. There's also the drama 'Liberal Arts,' which co-stars fellow Under-25er Elizabeth Olsen as his love interest.
Did You Know? Efron refuses to participate in social media (Twitter, Facebook) to ensure he keeps his private life private.