Anne Hathaway almost collapsed during filming for Les Miserables.
The 30-year-old star lost around 11kg while she was preparing for the role of Fantine, after putting herself through a diet of just porridge to make herself look ill.
She told the Metro newspaper: "I didn't think I would be able to keep going without collapsing. But I had to appear dead."
Hathaway has also warned fans from trying to copy her fasting, but admitted she would understand the temptation.
She said: "When I was a teenager, I would have tried anything that an actress I liked was doing to get thin."
As well as her extreme weight loss, Hathaway had her hair cropped for the film - and she revealed that it was a difficult, but necessary, sacrifice.
The Dark Knight Rises star said: "If you are not willing to cut off your hair, lose weight and look an idiot singing, the role is not speaking to you enough.
"On the day it was cut, I was trembling. Afterwards, there was a real feeling of absence.
"I don't think about [the hair] much now; I always loved being a low-maintenance girl. Now I am no-maintenance girl."
Her dedication to the role has paid off. As well as collecting a Golden Globe award for Best Supporting Actress on Sunday (13 January), the actress is tipped to do the treble by adding a BAFTA and Oscar to her recent collection.
However, the humble star won't allow herself to get carried away with being an awards favourite.
She admitted: "That's hugely flattering but nothing is real yet. It's so easy to get swept up in this but I'm just trying to keep my feet on the ground at the moment.
"I still can't believe I'm the girl who got to play Fantine."
Get more from iafrica.com: