Anne Hathaway had to "change her lifestyle" to play Catwoman in 'The Dark Knight Rises'.
The actress worked hard to get into shape to become the villain in the action film, so she could perform her own fight sequences and stunts.
She said: "I had to change my lifestyle in order to play this character. Nobody told me to lose weight, but I was told I had to be strong enough to do my own fight scenes, so I spent several weeks getting into the best physical shape I could.
"I made sure I got to the gym and made a conscious effort to make healthy food choices, and yes, I did feel healthier. Not only did I have to get into shape, but I had to maintain it for the ten months of shooting. I definitely did learn better eating habits during that time."
However, soon after shooting the film, Anne had to dramatically lose weight for her role as tuberculosis-ridden prostitute Fantine in 'Les Miserables', which provided a completely different and difficult challenge for her.
She added to Britain's Hello! magazine: "I lost 25lb. It was very hard. I lost the first 10 in three weeks and the subsequent 15 in the next two weeks. I don't recommend anyone try this. It was not designed with any health benefits in mind except to make me look like an impoverished prostitute who was near death.
"I'm back to my usual weight now and feeling fine, but while shooting the film I didn't look healthy or good and wasn't supposed to. Dying of tuberculosis is not romantic and it's not pretty."