It’s Selena Gomez!

At 21 years old, Miss Gomez is already a household name. She got her start on the Disney Channel in 'Hannah Montana,' and went on to star in several kid movies before releasing a studio album that went gold in 2011.

This year, Selena has made an easy transition into grown-up movies, and has been cast in seven upcoming films, alongside such big names as James Franco and Ethan Hawke. Gomez is currently dating a Bieber.