Rooney Mara, Elle Fanning, Melissa McCarthy and Shailene Woodley also up for Breakthrough Performance on Sunday.
By Kara Warner

Liam Hemsworth
Photo: Gary Gershoff/ WireImage

How do you know you've made it as an actor in Hollywood? When you land an MTV Movie Awards nomination in the buzzworthy Breakthrough Performance category!

In the past, the award has gone to such illustrious and soon-to-be superstars like Alicia Silverstone in 1994 for "The Crush," George Clooney in 1996 for "From Dusk till Dawn," Matthew McConaughey in 1997 for "A Time to Kill" and, more recently, Robert Pattinson in 2009 for "Twilight" and Chloë Moretz in 2011 for "Kick-Ass."

Who will join the long list of MTV breakthrough performers this year? Your guess is as good as ours as this category will be decided by a group of established directors rather than by public voting. Here's a closer look at the 2012 crop of nominees which are diverse as ever and range from an impoverished warrior to a dangerous hacker to a government employed puppy hoarder.

Elle Fanning, "Super 8"
There was a lot going on in J.J. Abrams' nostalgic sci-fi thriller, but the heart and soul of the film was its youngest actors, particularly scene-stealer Elle Fanning as the perfectly crushworthy and resilient Alice. She also does a killer zombie impression.

Liam Hemsworth, "The Hunger Games"
From the moment Liam Hemsworth was announced as Gale Hawthorne in "The Hunger Games," fans around the world were eager to see what the Aussie actor would do with the role. When the movie opened back in March, Hemsworth's strong, stoic and supportive take on the beloved character did not go unnoticed and made us even more eager to see him in the sequel, "Catching Fire."

Melissa McCarthy, "Bridesmaids"
The "Bridesmaids" cast is full of such wonderfully colorful and memorable characters, it's difficult to single out just one, but on the subject of the breakthrough performance in that hugely successful film, Melissa McCarthy's quirky, headstrong, security-obsessed, puppy hoarder Megan totally and completely stole the show.

Rooney Mara, "The Girl With the Dragon Tattoo"
One look at Rooney Mara as Lisbeth Salander in "The Girl With the Dragon Tattoo" and you can see the actress' commitment to the role, without her uttering a single word. Mara's transformation is as remarkable as her compelling, calculated and cold take on the brilliant hacker/master of revenge/mystery solver extraordinaire.

Shailene Woodley, "The Descendants"
Woodley's portrayal of the angsty teenager who becomes an anchor for her grieving dad in last year's awards-season darling "The Descendants" has officially put her on the map of young stars to watch and nabbed her several other acting awards to boot. And who can forget that underwater crying scene?

Head over to MovieAwards.MTV.com to vote for your favorite flicks now! The 21st annual MTV Movie Awards air live Sunday, June 3, at 9 p.m. ET.