Jeremy Irvine interview: 'I stopped eating for role in The Railway Man' His first act was losing two stone in two months. "I had a dietitian but I quickly realised to get where I wanted to be, I was going to have to go beyond what was healthy, so I just more or less stopped eating," he says. I moved back to my parents in the countryside and walked around the fields all day with my script, to burn calories but also to access the isolation which was so important to this character. He had to disappear inside his own head to get away from all the horrible things happening to him physically. I think I scared my mum a bit. Filming the torture scenes in Thailand, Irvine actually agreed to undergo waterboarding, when water is poured over a cloth covering the victim's face, giving them the sensation of drowning. We could have faked those scenes, but then it would have been something I'd made up and I was clutching at anything for a little glimpse of what Eric had been through. It really wasn't a big decision to do it, I could stop whenever I wanted, while Eric had it done to him for days on end. But it was horrible. I'd heard it described as drowning on dry land, but it's infinitely worse. Water is being forced into your stomach, lungs, nose, mouth, ears, eyes. When the hose comes out you just throw up a load of water. Suddenly, he snaps out of the monologue. I've got to be careful what I say because I hate it when actors say they suffered for their art. It sounds so pretentious. I just felt a real responsibility to Eric and his family and in a way to Colin who was going to play him later on. A self-confessed history "geek," Irvine was awestruck to meet Lomax, who died last year, at his home in the Scottish Borders. Eric was having terrors until the day he died. There were moments when we were talking when he'd disappear, he just wasn't in that room any more. Seeing someone suffering so badly in his nineties was very poignant. "In the First and Second World Wars, you had these ordinary people being thrown into extraordinary circumstances," he continues. Today we have career soldiers, but Eric worked in a post office and was thrown into the worst circumstances imaginable. His vulnerability is what makes it so moving. He wasn't an Arnold Schwarzenegger action hero, he was a slightly nerdy young man. Jeremy Irvine's transformation into a POW Another challenge, which Irvine brilliantly lives up to, was to resemble Firth's older version of Lomax without resorting to caricature. With Colin it's all about the mouth, you've no idea how much I've studied his. My brothers always say I have bum lips," he says, pouting. So I spent a lot of time sucking them in to look like him. Tall, blue-eyed (he wore brown contact lenses filming) and with a cute dimple, Irvine has matinee idol looks. He's also extremely charismatic, though not quite as adept at subtly reading messages on his phone, concealed under the sleeve of his leather jacket, as he might imagine. But it's abundantly clear that he wants to be far more than a heart-throb. "I'm very aware of what a fickle industry this is, there's a bloody quick turn around of actors, a couple of bad choices of roles and you can just be out," he says earnestly. Irvine (his real name is Smith, but he uses his grandfather's first name) stresses his success wasn't overnight. Before Spielberg cast him, he'd been busy making a showreel of fake work, which he touted around agents. I'd been working hard. I'm a great believer in making your own luck and the days of sitting around waiting for the phone to ring are over. Cameras are so cheap now, editing equipment is free to download, so if you're not in work you can be making your own work. The son of an engineer and a local government official and oldest of three brothers, Irvine was six when he was diagnosed with Type 1 diabetes. When I was eight I was on about eight injections a day, I administered them myself - I've always had a bit of a control issue there. I can eat whatever I want now, but as a child not so much. I was dreading my little brother being diagnosed too. It sucks for little kids not always being able to go out and play, but he's 15 now, so maybe it's not going to happen. He supports the Junior Diabetes Research Foundation but becomes faintly agitated, eyes flicking to his phone, when he's asked about his condition now, saying advances in medicine mean it's no longer an issue. "Everyone has something that they have to deal with and I'm very lucky that my thing doesn't affect me in a huge way," he says. But at his independent day school, Bedford Modern, his diabetes meant the other boys gave him a "tough time." I never fitted in, which is what led me to acting. I was looking for something different. Then when I was 16 I went backstage at Phantom of the Opera and found people I got on with. None the less, the school's strong military traditions meant his first career choice was to join the Army, again - it seems - as a way of proving himself. I was trying to p--- off my mum, anyway they wouldn't have me because I was diabetic. Drama school seemed like the next best thing. It was sold to me as a place where 2,000 people apply and 15 get in and they beat the s--- out of you, which appealed to me. But I got there and it wasn't quite that. He quit after a year, but only found roles in a teenage television movie and as a tree in an RSC production. I hit rock bottom and really did think I'd just wasted three or four years of my life. My dad wanted me to get a job as a welder at his company. But then Spielberg called. Since War Horse Irvine has made seven more films, including Great Expectations where he played Pip, The Reach, co-starring Michael Douglas, and A Night in Old Mexico next to Robert Duvall. He's currently filming Angel of Death, a sequel to 2012's hit The Woman in Black. There's loads of kids in it. Between takes I spend a lot of time hiding in cupboards and jumping out at them. I have one decent magic trick and they think I'm Dumbledore. It's brilliant. Irvine's still emerging from his chrysalis, half boy who loves such japes and refers constantly to his family, half man - intently discussing his "foreign value" (his ability to help a film sell internationally). He shares a flat in north London with his "best mate" and, apart from an apparently brief romance with pop star Ellie Goulding, steers clear of the showbiz scene. I take my mum to premieres. She really enjoys the parties, I always feel uncomfortable. He's almost obsessive about not letting fame go to his head. His two younger brothers tease him about his work, calling it "pretending" and when he once name-dropped to friends, they pointed out he was hardly a paramedic. My parents do a lot of community work, it's very humbling. There's never a chance of anyone thinking I'm doing anything earth-shattering, when the others are doing genuinely good stuff. The Railway Man is out today