Jeremy Irvine has admitted he scared his mum by losing so much weight for his role in Colin Firth's new film.
The War Horse actor plays a younger version of Colin's character in upcoming war drama The Railway Man, a British army officer who was sent to a Japanese prisoner of war camp during World War Two and forced to work on the infamous 'Death Railway' from Thailand to Burma.
And he revealed he lost two stone for the part by not eating for two months.
"I really scared myself and certainly my mum. I don't think I'd put myself through that again, but this merited it," he said. "A man died for every single sleeper laid on that track, it's extraordinary, but we don't seem to know about it."
Jeremy revealed he leapt at the chance to star in the film.
"Sometimes you read a script and spend a long time saying, 'Oh well, maybe it could work this way', but this was just such a 'I've got to do this movie' moment," said the 22-year-old.
"I met Colin Firth and had dinner with him and he was the one that actually got me the role, which was nice..."
He also loved working with Colin.
He said: "We kind of share the movie and he was so generous. We'd rehearse in his living room and I was thinking, 'My God, this is the kind of acting masterclass you can only dream of when you're at drama school'.
"At the time, you're just working with someone who's really good at what they do and really interesting, and of course afterwards you go, 'Wow, that was really kind of him'."