Domhnall Gleeson has revealed that he lost so much weight for his role in World War Two drama Unbroken that his contact lenses stopped fitting his eyes.
Angelina Jolie's Unbroken tells the story of Olympic long-distance runner and Air Force bombardier Louis Zamperini (played by Jack O'Connell), and his struggles to survive as a prisoner of war of the Japanese before the end of the war.
Before his capture, Zamperini's plane crashes into the Pacific Ocean and he is stranded at sea with two other soldiers, one of which is Domhnall's character Francis McNamara.
"It was a great experience. A tough one but a great one," Gleeson admitted.
The soldiers' plight at sea and experience at a prisoner of war camp meant that Domhnall had to lose weight for the role.
"Towards the end, getting toward the dehydration phase, I had to wear these contact lenses, because their eyes were red," he said.
"My contact lenses stopped fitting my eyes, because I was so dehydrated and had lost so much weight that everything had changed.
"But we were still trying to screw them in there - and you were hungry and overworked and physically and mentally exhausted - so then it got to the place where it wasn't much fun.
"Angie reminded me of it. I had forgotten totally. I've shut out some of the experience," he told the Huffington Post.
The coming year is set to be jam-packed for the 31-year-old as he is appearing on stage with his dad Brendan and his brother Brian in The Walworth Farce at the Olympia, but he is also starring in Alex Garland's Ex Machina; Brooklyn with Saoirse Ronan and Star Wars: The Force Awakens.
His role in Star Wars is one of his biggest to date and he will be excited to see the finished product next December.
"It just made me very excited," Gleeson said of watching the trailer for the first time.
"I felt like a kid again. I finished it with a big stupid smile plastered on my face.
"It was exactly the kind of feel that I was hoping the movie would have. If the movie feels the same way as the trailer, we're going to be in good shape," he added.