Transcript for Sally Field on Journey from 'Gidget' to 'Lincoln'
If you're looking for proof that Sally Field was dedicated to winning the role she played in Steven Spielberg's movie -- him. Consider this she agreed to gain 25 pounds to play the -- Yet it was her secret challenges she says off screen that propelled her performance forward. Here's ABC's Chris Connelly for her series Oscar confidential. Sally Field has been a beloved part of American pop culture for nearly a half century. -- sixties it comes -- Flying Nun. -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Today at 66. She has as many best actress Academy Awards as Merrill Streep does still she was undaunted and unabashed. And her desire to play Mary Todd Lincoln alongside Daniel Day-Lewis in Steven Spielberg's Lincoln. Madam president keeps me so I'm proud of -- film. I'm proud of my work in the film. I'm product fought to get and it. Proud -- to have done it all and grass while deep in the throes of a personal heartbreak. She has never before discussed unless mrs. Lincoln I demand that you. Try and get this acclaimed performance for which she poured through books on the troubled First Lady and gained 45 pounds nearly didn't happen despite Spielberg's initial enthusiasm. For her playing the part because even though -- -- said -- -- Mary Todd Lincoln. What had happened. I just knew. That it would be a battle that in because and teen years older than Daniel. And Mary was teen years younger than Lincoln and twenty years older than what Mary was -- -- it's it's Africa work. But Spielberg decided to give her one final chance customarily -- Day-Lewis had offered to fly from Ireland to Los Angeles for the day. To act with her. When he walked across the room I was sitting is Marion -- did not rise until he was literally next to me. She gave him my hand and he kissed it and I said mr. Lincoln. And he said mother and I whispered thank him. And he kissed the top of my hand and said my honor. And it will be one of the things I remember. For ever and ever and after. As she drove home Day-Lewis and Spielberg called. To say she'd won the role. -- -- -- That performance earned field a supporting actress Oscar nominations -- already stimson. As the pinnacle of an acting career transformed. By a key moment of self assertion way back in 1972. What happened when you told your agent. I wanna do TV anymore I want to movies they said will you this foolish to secede you'll never work continue not pretty enough in a good enough. And I think tired. When -- business manager said the same thing I think you're fired. Is fired everybody and I left my husband you know like out how do you. The results would speak for themselves she would win -- best actress Oscar in 1980 for warmer red. Another in 1985. Replaces in the heart. The speech and hearing feline would enter Oscar lore. And I can't deny the fact that -- Like. -- field there is much to be proud of three suns -- grand kids but this LA native and new home in New York City. And Lincoln the performance achieved under more challenging circumstances. -- she has previously -- Well. My mother passed away while -- was doing Lincoln. Which is a huge part of the whole experience. I have never really talked about it -- natural home and she'd been very -- consult with aren't going. Of course the greeting in the -- that I felt we're tremendous history tremendous. Margaret field -- was herself an actress in television and in films. It was like her get. You know you and again it's just what's very very hard but. It was. The way it's supposed to be I felt finally you know that she had gone like this. And then the -- that I had then. Right -- hand just. How do I left. And went -- to do things I was. -- -- to do and I'm Chris Connolly for Nightline. In Los Angeles. Sally Field you can watch the Academy Awards right here on ABC Sunday February 24.
This transcript has been automatically generated and may not be 100% accurate.