Emily Blunt says the entire crew of Oppenheimer, including the scientific advisors, read American Prometheus before beginning filming.

The British actress said the 2005 biography of the US theoretical physicist had been “super helpful” and contained “endless nuggets” to help with character development.

Blunt stars alongside Cillian Murphy and Florence Pugh in the film, directed by Christopher Nolan, which tells the story of the “father of the atomic bomb”.

It is based on the Pulitzer Prize-winning book American Prometheus: The Triumph and Tragedy of J Robert Oppenheimer, written by Kai Bird and Martin J Sherwin.

Oppenheimer photocall- London
(left to right) Emily Blunt, Cillian Murphy and Florence Pugh, arrive for the photo call for Oppenheimer (Ian West/PA)

Speaking at a photocall for the film in London on Wednesday, Blunt recalled preparing for the role while flying out to New Mexico to begin production.

“We all read American Prometheus,” she told the PA news agency.

“I remember on the flight to New Mexico when it was starting – everyone on board was reading that book, the entire (crew)… all the scientists were reading the book.

“We’re all trying to cram it before we started, but it was super helpful. There were endless little nuggets and wonderful little nuances to think about the characters.”

Oppenheimer photocall- London
Cillian Murphy plays the title role in Oppenheimer (Ian West/PA)

Blunt added that the script for Oppenheimer had been “so visceral and so evocative” that there had been “nothing to invent”.

“It was all there,” she said.

Murphy, who plays the title role in Oppenheimer, told PA that he had received the call for the role “out of the blue” from Nolan’s wife, Emma Thomas – the film’s producer.

He said: “That’s Chris’ MO (modus operandi)… he said, ‘I’m making a movie about Oppenheimer and I’d like you to play Oppenheimer’. So it was just a very pleasant shock.”

Asked about the moral responsibility of scientists in the modern age, Murphy continued: “I think whatever you think about that, we’re all living in Oppenheimer’s world now.

“We’re all living in the nuclear age that he created.”

Oppenheimer is due for release in UK cinemas on July 21.