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OTRC: Sally Field: I gained 25 pounds for 'Lincoln' (Photos, Video)

Sally Field talks to OTRC.com about 'Lincoln.' / Sally Field attends the premiere of 'Lincoln' at Grauman's Chinese Theatre in Hollywood on Nov. 8, 2012. / Sally Field appears in a scene from Dreamworks Pictures' 'Lincoln,' which was released on Nov. 9, 2012. (OTRC / Eric Charbonneau / WireImage / Walt Disney Studios / Dreamworks Pictures)

The typically slim Sally Field underwent quite a body transformation to play President Abraham Lincoln's wife in the new film "Lincoln" - she put on 25 pounds.

Field, who recently turned 66, plays First Lady Mary Todd Lincoln in the movie, which was released on November 9. The actress has since slimmed back down.

"I weighed a lot more then than I do now - I put on 25 pounds for the role," the actress told OTRC.com. "The costumes could've competed in weight with me because we wanted her to be as authentically Mary as we possibly could be."

"So Joanna Johnson and I - the costume designer, who's so brilliant - we tried to go with the actual measurements that we knew she had, because they have records in her waist size and things, when she had clothes made, so we wanted to replicate that as much as we could," she said. "And I did, which was horrifying."

Field said that she and main star Daniel Day-Lewis, who plays the 16th President of the United States, did not wear prosthetics as part of their costumes.

"Daniel doesn't wear any prosthetics. I didn't have any padding," she said, adding: "You could see it in my face, in my chin, my arms - it was like 'Ugh!' There's a scene where I take off a great deal of those clothes and you can sort of see it."

Her secret to gaining the weight? Eating, obviously, for one. And in true "Mean Girls" style - weight gain products. The actress drank ProGain, a high-protein beverage consumed by bodybuilders that that the actress called a "horrible drink."

"Can you imagine to be a woman of a certain age and drinking something twice a day called ProGain?" she said, adding: "And you put nut butter - you put two huge tablespoons of nut butter in that. And then you eat those bars every two hours, that have, like, 400 calories each."

"I ate so many calories every day," she said. "I was, honestly, always afraid that I would drop dead somewhere along the line."

"Lincoln" was directed and produced by Steven Spielberg focuses on the U.S. president's final months in office, during which he pushes to end the Civil War, unite the people - including the politicians who oppose him - and pass legislation that would abolish slavery.

Field said she had to "fight" for her role.

"Steven had asked me to do it a long time ago, but then it was such a long time ago, by the time it came down to doing it and there was a script, and Daniel was involved, I knew it would be a fight," the actress said. "So I fought for it and Steven was generous enough to let me fight for it and hear me and Daniel was generous enough to come on board at one point and test with me."

"I was there, first of all, because some part of me became Mary and fought like crazy for it - and the generosity of those two brilliant men who let me fight for it and eventually let me win," she said.

Reporting by George Pennacchio of KABC Television, parent company of OnTheRedCarpet.com that also produces the entertainment show "On The Red Carpet"(check for local TV listings).

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