Cillian Murphy warns against Oppenheimer diet as he only ate 'an almond a day'

What's that saying? 'An almond a day keeps the doctor away'? No, that can't be right.

Obviously you need a lot more than an almond to keep you going each day, but that's basically all Oppenheimer actor Cillian Murphy was relying on as he worked to drop weight for his role in Christopher Nolan's upcoming drama.

The Peaky Blinders star portrays the man himself, J. Robert Oppenheimer; a theoretical physicist, the 'father of the atomic bomb' and a man who, as described by Murphy, was almost 'emaciated'.

It's not a word used to describe a healthy physique, but Murphy was determined to do justice to the role and so committed not only his mind, but also his body to accurately portray Oppenheimer.

Speaking with The New York Times, Murphy explained: "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."

Universal Pictures

Thankfully I don't think Murphy changed his diet solely to martinis and cigarettes, but his co-star Emily Blunt has indicated that it might not have been much better than that.

Speaking with Extra alongside Matt Damon, she said: "Cillian had to [remove himself from the antics on set] because he had such a monumental undertaking, and he could only eat, like, an almond every day because he was so emaciated."

Damon agreed that it definitely wasn't an easy role for Murphy, saying: "The sheer volume of work that he had and the level of detail that Chris [Nolan] demands, there was always something for him to be thinking about."

Though Murphy has stressed that he doesn't want to 'advise' against such weight loss, and wouldn't reveal exactly how much he lost.

He told The Guardian: "You become competitive with yourself a little bit which is not healthy. I don’t advise it... Ach, no. I don’t want it to be, ‘Cillian lost x weight for the part’.”

Universal Pictures

Part of Murphy's ability to lose so much weight came, as Damon said, due to the intense nature of the work, as he continued: "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 …hyper something. But it was good because the character was like that. He never ate.”

With filming now behind him, Murphy can thankfully start consuming more than almonds and cigarettes and prepare for everyone to see his hard work pay off on the big screen.

Oppenheimer is set to be released in cinemas on 21 July.

If you've been affected by any of the issues in this article and would like to speak with someone in confidence, call the BEAT Eating Disorders helpline on 0808 801 0677. Helplines are open 365 days a year from 9am–8pm during the week, and 4pm–8pm on weekends and bank holidays. Alternatively, you can try the one-to-one webchat.