Murphy stars as nuclear scientist J Robert Oppenheimer in the film, which is released this month, with a significant subplot involving his relationship with psychiatrist and physician Jean Tatlock, played by Pugh.
Speaking to The Guardian, Murphy said he was under “strict instruction” not to discuss any of the film’s plot specifics, but did disclose details on the film’s chemistry tests between him, Pugh and Emily Blunt, who portrays Oppenheimer’s wife Kitty.
“They put two actors in a room to see if there’s any spark, and have all the producers and director at a table watching,” he recalled. “I don’t know what metric they use, and it seems so outrageously silly, but sometimes you get a chemistry and nobody knows why.”
The report also added that Murphy and Pugh have scenes of “prolonged full nudity” together, and that it makes Oppenheimer one of Nolan’s rare films to include a significant interest in sex and relationships.
Fans theorised that Nolan would venture into this territory in June, when it was revealed that Oppenheimer had received the filmmaker’s first “R” rating in the US since his 2002 film Insomnia.
An R rating is roughly equivalent to a “15” in the UK, although age ratings for any one film vary depending on the discretion of each country’s ratings bodies. A PG-13, meanwhile, is considered more or less equivalent to a “12A” in the UK.
Oppenheimer received its R rating for “some sexuality, nudity, and language”, while in the UK it has received a 15 certificate for “strong language and sex”.
The film remains one of the most hyped blockbusters of this summer, with Nolan last month teasing that it had left early viewers “devastated”.
“They can’t speak. I mean, there’s an element of fear that’s there in the history and there in the underpinnings,” the director said.
As well as Murphy, Pugh and Blunt, Oppenheimer features a large cast that includes Matt Damon, Robert Downey Jr, Rami Malek, Gary Oldman, Dane DeHaan, Josh Hartnett, Kenneth Branagh, Matthew Modine, Casey Affleck, Alden Ehrenreich, and Jason Clarke.
Blunt this week revealed that the cast bonded while filming the movie in the New Mexico desert in 2022, but that Murphy declined to participate in the cast’s group dinners.
“The sheer volume of what he had to take on and shoulder is so monumental,” the A Quiet Place star said. “Of course he didn’t want to come and have dinner with us.”
Oppenheimer debuts in cinemas on 21 July, the same day as Greta Gerwig’s Barbie. Eager fans are already planning on buying tickets to see both films back-to-back. The viral trend, dubbed “Barbenheimer”, has become so popular that even Murphy, Margot Robbie and Tom Cruise have publicly supported it.