Cillian Murphy reveals the most important lesson Oppenheimer taught him at the BFI screening of his Oscar-nominated film

Cillian Murphy has revealed what he thought about playing J. Robert Oppenheimer in his Oscar-nominated film.

The Irish actor attended a screening of Christopher Nolan's biopic at the BFI IMAX Waterloo on Wednesday, where he spoke about the research that went into his role as the theoretical physicist considered the “father of the atomic bomb.”

When asked about the biggest lesson he learned from working on the film, Cillian thoughtfully replied: “The most important thing I learned or relied on was that he was human, that was the most important thing , what I wanted to access – his humanity.”

The incredible physical transformation Cillian underwent for the role was revealed by his co-star Emily Blunt, who plays Oppenheimer's wife Kitty.

Emily recalled how Cillian only ate “one almond a day” and became “so thin” as he immersed himself in the project.

Cillian Murphy has revealed what he thought about playing J. Robert Oppenheimer in his Oscar-nominated film

Cillian Murphy has revealed what he thought about playing J. Robert Oppenheimer in his Oscar-nominated film

The Irish actor attended a screening of Nolan's biopic at the BFI IMAX Waterloo on Wednesday, where he spoke about the research that went into his role as a theoretical physicist

The Irish actor attended a screening of Nolan's biopic at the BFI IMAX Waterloo on Wednesday, where he spoke about the research that went into his role as a theoretical physicist

Speaking to Extra last year, Emily explained: “He had such a monumental undertaking.”

Cillian herself told The New York Times: “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.”

But Cillian made it clear that his extreme diet was not safe and should not be tried by other people. “You get a little competitive with yourself, which is not healthy,” he said, adding, “I advise against it.”

The rapid pace of filming helped Murphy achieve his weight loss goal.

“It's like you're on this damn train that's just bombing.” It's a bang, bang, bang, bang. “You sleep for a few hours, get up and do it again,” he told the Guardian.

“I ran with crazy 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…something,” he explained.

“But it was good because of what the character was like. He never ate.'

When asked about the biggest lesson he learned from working on the film, Cillian thoughtfully replied:

When asked about the biggest lesson he learned from working on the film, Cillian thoughtfully replied: “The most important thing I learned or relied on was that he was human.”

Cillian took part in a question and answer session with the film's composer Ludwig Göransson, editor Jennifer Lame and cinematographer Hoyte van Hoytema

Cillian took part in a question and answer session with the film's composer Ludwig Göransson, editor Jennifer Lame and cinematographer Hoyte van Hoytema

The incredible physical transformation Cillian underwent for the role was revealed by his co-star Emily Blunt, who plays Oppenheimer's wife Kitty

The incredible physical transformation Cillian underwent for the role was revealed by his co-star Emily Blunt, who plays Oppenheimer's wife Kitty

Cillian, 47, continued his winning streak in the nominations, picking up a Best Actor nod for his title role in “Oppenheimer.”

He is currently the bookmakers' frontrunner for the prize and will face Bradley Cooper – Maestro; Colman Domingo – Rustin; Paul Giamatti – The Holdovers and Jeffrey Wright – American Fiction.

Oppenheimer emerged with 13 nominations and won Best Picture honors. Best Director for Christopher Nolan and Best Supporting Actor or Best Supporting Actress for Robert Downey Jr. and Emily Blunt.

Director Christopher Nolan has been nominated for five Oscars in the past for his films “Momento”, “Inception” and “Dunkirk” – but never won.

He's hoping to turn his fortunes around with his three-hour epic about the creation of the atomic bomb, which has been one of the favorites of awards season so far.

He will be against Justine Triet – Anatomy of a Fall; Martin Scorsese – Killers of the Flower Moon; Yorgos Lanthimos – Poor Things and Jonathan Glazer – The Zone of Interest in the directing category.

Robert hopes his portrayal of United States Atomic Energy Commission Chairman Lewis Strauss will win him the Best Supporting Actor award.

Over in New York, Matt Damon attended another screening of the blockbuster film.  The actor plays General Leslie Groves, the director of the Manhattan Project, in the film

Over in New York, Matt Damon attended another screening of the blockbuster film. The actor plays General Leslie Groves, the director of the Manhattan Project, in the film

The film's producer, Emma Thomas, and director Christopher Nolan also attended the Q&A

The film's producer, Emma Thomas, and director Christopher Nolan also attended the Q&A

Oppenheimer has 13 Oscar nominations and won Best Picture awards;  Best Director and Best Supporting Actor and Best Supporting Actress for Robert Downey Jr. and Emily Blunt

Oppenheimer has 13 Oscar nominations and won Best Picture awards; Best Director and Best Supporting Actor and Best Supporting Actress for Robert Downey Jr. and Emily Blunt

He will compete against Sterling K. Brown – American Fiction; Robert De Niro – Killers of the Flower Moon; Ryan Gosling – Barbie; Mark Ruffalo – Poor things.

Meanwhile, Emily – who played Oppenheimer's wife Kitty – will take on Danielle Brooks – The Color Purple; America Ferrera-Barbie; Jodie Foster – Nyad; Da’vine Joy Randolph – The Holdovers.

Oppenheimer's box office rival Barbie received eight nominations, including awards for Best Picture; Ryan Gosling for Best Supporting Actor; and two candidates for best song.

However, Greta Gerwig was left out of the “Best Director” category.