Christopher Nolan explains why it was 'essential' to showcase sex scenes in 'Oppenheimer'

• Christopher Nolan has never done a sex scene in one of his movies until "Oppenheimer."
• Nolan told Insider it was an "essential part" of J. Robert Oppenheimer's story.
• An affair with a Communist, played by Florence Pugh in the movie, led to him losing his security clearance.

You likely know J. Robert Oppenheimer best as the father of the atomic bomb.

After seeing "Oppenheimer," you will also know him as a ladies' man.

Christopher Nolan's latest movie recounts Oppenheimer's work in the Manhattan Project, but it also reveals that the renowned physicist had several affairs while he was married, including one with a Communist, which got him into hot water.

Because of this side of Oppenheimer's life, Nolan featured something he's never done before in his filmography: sex scenes.

"When you look at Oppenheimer's life and you look at his story, that aspect of his life, the aspect of his sexuality, his way with women, the charm that he exuded, it's an essential part of his story," Nolan told Insider about the choice of including sex scenes.

One woman in particular holds an important part in the "Oppenheimer" story.

Jean Tatlock, played by Florence Pugh, is someone Oppenheimer is completely infatuated with leading up to the Manhattan Project.

Their steamy love affair continues after Oppenheimer, played by Cillian Murphy, marries Kitty, played by Emily Blunt.

But Tatlock is also a Communist. Due to her political affiliations, Nolan said his affair with her "had enormous ramifications for his later life and his ultimate fate."

Essentially, a decade after Oppenheimer successfully tested the atomic bomb, his security clearance was revoked following a 1954 security hearing in which he was accused of having Communist ties.

Nolan said he wanted the sex scenes between Oppenheimer and Tatlock to show why the relationship transcended politics.

"It felt very important to understand their relationship and to really see inside it and understand what made it tick without being coy or allusive about it, but to try to be intimate, to try and be in there with him and fully understand the relationship that was so important to him," he said.

Nolan also answered whether he's nervous about how audiences will react to seeing sex scenes in one of his movies.

"Any time you're challenging yourself to work in areas you haven't worked in before, you should be appropriately nervous and appropriately careful and planned and prepared," he said.

Nolan gave all the praise to his actors: Murphy, who he has worked with on several movies, and Pugh, who he's wanted to work with.

"I met with her and immediately felt a creative connection," he said of the acclaimed "Little Women" actor. "I felt this is somebody who could bring Jean Tatlock to life and have the audience understand the significance of this figure in Oppenheimer's life."

"Oppenheimer" opens in theaters on Friday.