Liam Hemsworth
Age: 21
What He's Done: Starred opposite his girlfriend, Miley Cyrus, in 'The Last Song,' and was a big hit in his native Australia on the primetime soap opera 'Neighbours.'
What's Next: His star power is about to hit an all-time high when he takes on the role of Gale in 'The Hunger Games' opposite fellow Under-25ers Jennifer Lawrence and Josh Hutcherson. He's also slated to star in 'The Expendables 2' with action heroes Bruce Willis and Sylvester Stallone.
Did You Know? He almost landed the title role in 'Thor,' but his brother, Chris Hemsworth, landed it instead.