In anticipation of Christopher Nolan's Oppenheimer, the measures Cillian Murphy took to achieve the weight loss necessary for the role have been revealed and, understandably so, he advises against it.

Speaking in an interview, he co-star Emily Blunt said, 'He had such a monumental undertaking. And he could only eat, like, an almond every day. He was so emaciated.'

The eagerly awaited Oppenheimer will be released July 21, and the role required drastic changes to his diet, but a healthier looking Murphy in comparison to filming could be seen walking the red carpet.

Murphy, 47, told the New York Times, 'I love acting with my body, and Oppenheimer had a very distinct physicality and silhouette, which I wanted to get right.'

'I had to lose quite a bit of weight, and we worked with the costume and tailoring; he was very slim, almost emaciated, existed on martinis and cigarettes.'

While the Inception star didn't replicate J. Robert Oppenheimer's diet of cigarettes and martinis, the exact methods he underwent to make weight haven't been disclose. However, it has been insinuated that the diet was incredibly restrictive.

Speaking about his weight loss, he mentioned that he almost got caught in unhealthy habits, pushing things a touch too far. 'You become competitive with yourself a little bit which is not healthy. I don’t advise it,' he told the Guardian.

He also explained how he doesn't want his weight loss methods to become the story. 'I don't want it to be; Cillian lost X for weight for the part.'

Murphy did reveal how he kept going through filming, even in the face of extreme calorie restriction. 'It’s like you’re on this fucking train that’s just bombing. It’s bang, bang, bang, bang. You sleep for a few hours, get up, bang it again,'

'I was running on crazy energy, I went over a threshold to where I was not worrying about food or anything. I was so in it, a state of hyper. But it was good because the character was like that. He never ate.'