The stars of upcoming blockbuster ‘Oppenheimer’ have revealed the ‘grueling’ efforts Cillian Murphy went through to become the ‘father of the atomic bomb’ – and said the actor ate ‘an almond a day’ to help himself in the ‘ to transform “emaciated” physicist.
The 47-year-old ‘Peaky Blinders’ star plays J. Robert Oppenheimer in Christopher Nolan’s biopic, which is due out in theaters on Friday. She accompanies the scientist in the development of the atomic bomb during World War II as part of the top-secret Manhattan Project.
Cillian has previously detailed the extreme lengths he went to to portray the physicist on screen, who loses weight to reflect his “nearly emaciated” physique.
His co-star Emily Blunt opened up about Cillian’s drastic change, saying he survived on a grueling diet of just one “almond a day.”
In an interview with Extra, Emily – who plays his wife Kitty on screen – described the “monumental endeavor” of losing weight for the role.
Transformation: Cillian Murphy (left in 2017 and right in July 2023) underwent a drastic transformation to portray the “father of the atomic bomb” J. Robert Oppenheimer in the biopic
Drama: Directed by Christopher Nolan, the epic follows Oppenheimer (Cillian starred in filming last year) as he directs the laboratory designing the atomic bomb during World War II
She said, “He had such a monumental endeavor.” And he could only eat about one almond a day. He was so emaciated.’
Cillian Murphy spent five months transforming his body for Oppenheimer
Cillian warned his transformation wasn’t “healthy”.
Speaking to The New York Times, the star revealed that before filming began, it took him more than five months to prepare for the role both physically and emotionally.
He admitted he “liked” the physicality of preparing for the role and said he wanted to lose weight so he could “big-eyed” Oppenheimer to show he’d “never eaten.”
He said, “I love playing with my body and Oppenheimer had a very distinct physicality and silhouette that I wanted to get right.”
“I had to lose some weight and we worked on the costume and tailoring; he was very slim, almost emaciated, lived on martinis and cigarettes.
“He had these really bright eyes and I wanted to give him this wide look, so we worked a lot on his silhouette and facial expression before we started.”
Extreme: Cillian (pictured in April) didn’t shy away from describing the extreme lengths he went to to portray the physicist, who loses weight to reflect his “nearly emaciated” physique
Weight loss: His co-star Emily Blunt has been open about Cillian’s transformation, revealing that he only ate “one almond a day” (he is pictured at Peaky Blinders on the left in 2021 and on the right in July 2023)
Drastic: Cillian (pictured in July 2023) also shared how he tested himself on how little he could eat while preparing for the role and confessed he “doesn’t advise” on the extreme diet.
Real life: Cillian explained that Oppenheimer (pictured) “never ate” and lived on “martinis and cigarettes”.
Cillian Murphy advises against extreme dieting after losing weight for Oppenheimer film
Cillian also said he tests himself how little he can eat and confessed he “does not advise” the extreme diet.
He told The Guardian: ‘You get a little bit competitive with yourself, which isn’t healthy.’ I advise against it.’
The actor said he wouldn’t reveal exactly how much weight he lost for the role, but opened up about how the rush of filming made him stop worrying about food.
He slept for a few hours during filming, he said, adding, “I had insane energy; I crossed a threshold where I no longer had to worry about food or anything like that.
“I was so into it, in a state of hyper… hyper-something, but it was good because the character was like that. ‘He never ate.’
Cillian also shared how director Nolan gave the stars about six months to prepare before filming began.
He told the Associated Press, “We had a lot of time to prep, Chris always puts a lot of time into prep, which I really like, so we had about six months before we actually started filming.”
“You dive in, you dive in.”
Emily Blunt takes on the role of physicist Oppenheimer’s wife, Kitty, while Florence Pugh plays Jean Tatlock, a psychiatrist, Communist Party member and close friend of J. Robert Oppenheimer.
The film is based on the 2006 book American Prometheus: The Triumph And Tragedy Of J Robert Oppenheimer by Kai Bird and Martin J Sherwin.
The Pulitzer Prize-winning book details Oppenheimer’s personal life and his time leading the Manhattan Project in the early and mid-1940s.
Expected: Cillian takes on the role of Oppenheimer and critics have predicted the film to be a huge success. He is pictured with Emily Blunt who plays his wife Kitty
Cast: Florence Pugh plays Jean Tatlock, a psychiatrist, Communist Party member and close friend of Oppenheimer
The film has been hailed as a contender for multiple awards.
Journalists have taken to Twitter to share their rave reviews of the film, with one reviewer describing how the film “cracked my brain” and “made me sob til the credits”.
Robbie Collin from the Telegraph wrote, “I’m torn between being coy and secretive about Oppenheimer and just coming out and saying it’s an absolute blast.”
Variety’s Elsa Keslassy added: “A sign that French audiences loved #Oppenheimer is that they stayed outside the Grand Rex cinema to debate it long after the film finished!”