Fergie
The Black Eyed Peas songstress gave her typically toned bod a girth-alicious makeover for Nine.
"We'd have Italian food every day," the movie's choreographer and coproducer John DeLuca told us. "Fergie would sit with the food and she really ate—like garbage. I'd sit there and be like, 'How can you digest that kind of food?'"
Jim Carrey
If you haven't seen Jim Carrey lately, it's not because he's hiding. He's putting on major poundage for a Three Stooges movie.
"He's going to gain fifty pounds to play Curly," Carrey's ladylove Jenny McCarthy told Ellen DeGeneres in April. "He's just having so much fun with it."
Matt Damon
People magazine's former Sexiest Man Alive, Matt Damon, sacrificed his Bourne Identity brawn to play Mark Whitacre in this year's The Informant.
"It was very, very fun—probably the funnest time I had working because I didn't have to go to the gym after work and I just ate everything I could see," the 39-year-old has said about gaining girth.
Russell Crowe
Russell Crowe devoured Sprinkles cupcakes and cheeseburgers for breakfast to gain 63 pounds to play Ed Hoffman in Body of Lies opposite Leonardo DiCaprio.
We can only imagine what he ate for lunch and dinner.
Jared Leto
Mr. Leto tipped the scales with 67 extra pounds to play John Lennon's assailant Mark David Chapman in Chapter 27.
"As I started to research, I realized that the physical representation of this guy had so much to do with who he was," Jared told the L.A. Times.
Janet Jackson
Janet Jackson's weight appeared out of control in 2006 as the sexy superstar prepped to play Krystal in Tennessee.
"I didn't recognize myself," the 43-year-old said. "It was so hard on my body."
And it turned out to be all for nothing. The role was eventually played by Mariah Carey after Jackson dropped out because of a scheduling conflict.
Charlize Theron
The South African beauty shocked us when we took one look at her as real-life serial killer Aileen Wuornos in Monster.
If 30 more pounds wasn't enough, she also transformed herself with bad skin, crooked teeth and shaved eyebrows.
"I was so concerned about wanting to stay true to Aileen, every decision we made, we never forgot Aileen," Theron, who went on to win an Oscar for her work, told the CBS Early Show. "When I saw it and when I see it today, I'm just really proud."
George Clooney
The always gorgeous George Clooney looked less-than-perfect, in Syriana. Hollywood's hottest bachelor packed on 30 pounds to play Bob Barnes in the award-winning thriller.
"I'm sort of happy at the idea that people—when they first see me in the movie or when they first see the poster, don't even know it's me," Clooney told Cinema Confidential. "That makes me proud."
Renée Zellweger
Renée Zellweger wowed viewers with her spot-on depiction of Bridget Jones in Bridget Jones' Diary and its sequel. But the role didn't gain attention solely for Zellweger's award-winning acting. She also packed on a reported 28 pounds.
Rumors began circulating that Zellweger was signed on for a third installment of the series. But unfortunately, the 40-year-old actress told us that indeed, those are only rumors.
Guess that means no fat suit!