10. Emma Stone
After several supporting roles in flicks like Superbad, The House Bunny and Zombieland, the starlet finally graduated to leading lady status with the smart, sexy high school comedy Easy A. Throw in her recent hosting duties on SNL and the news that she'll be appearing as love interest Gwen Stacy in the upcoming Spider-Man reboot and it's, er, easy to see why she's on our list.
9. Liam Hemsworth
We'll be the first to admit that most of the stories we wrote this year about the Aussie actor usually related to his on-again/off-again relationship with Miley Cyrus, his costar in The Last Song. But that's not why he made the cut here. Simply put, the guy's got it going on all on his own. Oh, and he's not too hard on the eyes either.
8. Chord Overstreet
You know you've arrived in Tinseltown when you become the new hot thing on Glee (gold lamé shorts and all), you're immediately linked to a Hollywood starlet and asked to bare it all for Playgirl. Unfortunately, we're all-too-aware of how that last one ended.
7. Betty White
We've all heard the saying, "what's old is new again." Well, there's no better example of that than this golden girl, who was introduced to yet another generation by way of a superfunny Super Bowl ad, a TV Land sitcom and a gig hosting SNL following a massive campaign on Facebook (Just to name a few). Heck, her popularity is so high right now, she's even become part of the Hollywood rumor mill. Then again, she is only 88 years young!
6. Mia Wasikowska
When you manage to hold your own against the likes of Johnny Depp in Alice in Wonderland as well as Annette Bening and Julianne Moore in The Kids Are All Right, we say this kid is all right.
8. Nicki Minaj
The Trinidadian rapper might be known as much for those outlandish wigs and outfits as she is for her music, but when your career immediately skyrockets as rapidly as her's (the first artist to appear on seven songs on the Billboard's Hot 100 simultaneously, hello!), she's probably entitled to wear whatever the hell she likes.
4. Chloe Moretz
The little lady behind Hit Girl became one of 2010's It Girls thanks to her much-talked-about performance in Kick-Ass as well as her chilling portrayal of a young vampire in the thriller Let Me In. The 13-year-old, who has since dropped her middle name "Grace," may soon no longer need her last name either seeing how quickly her star is rising.
3. Andrew Garfield
This hottie may not be a household name yet, but with Oscar buzz already building for his role in The Social Network, that may change very, very soon. Although, if he doesn't get a nod when nominations roll around, becoming the next Spider-Man just might do the trick.
2. Willow Smith
Sure, Will and Jada may have helped open up more than just a few doors for their daughter, but this 10-year-old definitely delivered on the nepotism by way of her infectious hit "Whip My Hair." Not to mention, imitation is still the sincerest form of flattery, right?
1. Rooney Mara
Between battling Freddy Krueger in the 2010 version of A Nightmare on Elm Street and facing off with Facebook founder Mark Zuckerberg (Jesse Eisenberg) in The Social Network, the actress definitely got noticed this year. Of course, beating out a ton of A-listers for the coveted role of Lisbeth Salander in the U.S. adaptation of The Girl With the Dragon Tattoo probably helped too.
Next Gallery: Top 10 Big Stories of 2010