Their movies might not be out yet, but Rachel McAdams and Zac Efron were among the stars honored for their upcoming work at this year's ShoWest Awards.

The annual convention and gala, held Thursday in Las Vegas, named McAdams -- who will appear in State of Play -- the Female Star of the Year. Dennis Quaid -- who voiced the lead role in the 3-D animated film, Battle for Terra -- was honored as Male Star of the Year.

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Quaid also stars in the much-hyped G.I. Joe movie, and he told Usmagazine.com how he was able to get into his military role.

"General Hawk to me is a cross between James Bond, General George Patton and Hugh Hefner," he told Us at the awards ceremony. "That's the way I took it. Kept it simple."

Sienna Miller, who won for Supporting Actress of the Year and also will appear in G.I. Joe admits she did a bit more research for her part.

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"I watched some of the old cartoons and lifted some from it," she told Us. "I knew enough about the character, the Baroness, and there were certain elements we tried to stay true to, but on the whole I think the G.I. Joe fans will be pleased with the film."

Efron, the young star of Disney's upcoming 17 Again, drew screams from the audience as he accepted his award for Breakthrough Performer of the Year.

Other up-and-coming stars -- including Chris Pine for Male Star of Tomorrow -- were recognized.

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The female cast of Sorority Row, which included The Hills' Audrina Patridge and Rumer Willis, also got awards for Stars of Tomorrow.

"I think they did a really good job making each character so different even though they are all females dealing with the same problems," Willis said about the horror film, which will be released in October.

Other winners included Zack Snyder for Director of the Year, Bradley Cooper for Comedy Star of the Year and Michael Caine for Lifetime Achievement.