Who plays who in Christopher Nolan's star-studded historical drama Oppenheimer

Christopher Nolan's Oppenheimer — now in theaters — details the development of the atomic bomb and has a huge cast of famous actors playing physicists, politicians, military-types, physicists, and more physicists. But which star is portraying which scientist and power player? Find out with our guide to the cast and their respective characters below.

Universal Pictures, Bettmann Archive Cillian Murphy in 'Oppenheimer' and the real J. Robert Oppenheimer

Cillian Murphy is J. Robert Oppenheimer

Nolan cast his longtime collaborator Cillian Murphy in the lead role of theoretical physicist J. Robert Oppenheimer, the so-called "father of the atomic bomb" who headed up the Manhattan Project during World War II. "No one knew what I was up to, no one knew what I was doing," Nolan told EW, explaining how he let Murphy know he wanted him for the role. "To be able to pick up the phone, be like, 'This is the one where you carry the movie and really get to show what you can do,' it's honestly one of my favorite moments in the movie business, when I had that conversation."

Melinda Sue Gordon/ Universal Pictures, CORBIS/Getty Emily Blunt in 'Oppenheimer' and the real-life "Kitty" Oppenheimer

Emily Blunt is Katherine "Kitty" Oppenheimer

Emily Blunt reunited with her A Quiet Place Part II costar Murphy to play Oppenheimer's wife Kitty, who moved to New Mexico with her husband after he took over the Manhattan Project. "I went and met Chris in L.A.," the actress explained during EW's Around the Table conversation, which took place before the start of the SAG-AFTRA strike. "So we talked for an hour or so, and then he's just very casual, and he goes, 'So it's the part of his wife and I'd love you to take a look at it.' And you're like, is this an offer? [Laughs] So I went into the living room and read the script and it was just so heart-racing. It was so awesome."

Universal Pictures, MPI/Getty Matt Damon in 'Oppenheimer' and the real-life Gen. Leslie Groves

Matt Damon is Leslie Groves

Interstellar actor Matt Damon returned to the Nolan fold to play Lt. Gen. Groves, the director of the Manhattan Project who appointed Oppenheimer to directly oversee the development of the atomic bomb. "I was so blown away by the script," the Bourne franchise star said. "It's in the first person, which I'd never seen before. So rather than say, 'Oppenheimer crosses the room' it says 'I walk across the room.' It has a visceral effect on you, and it pulls you right in, which is the point."

Melinda Sue Gordon/ Universal Pictures, Pictorial Parade/Archive Photos/Getty Images Robert Downey Jr. in 'Oppenheimer' and the real-life Lewis Strauss

Robert Downey Jr. is Lewis Strauss

Nolan gifted Iron Man star Robert Downey Jr. the plum supporting role of Lewis Strauss, the chairman of the Atomic Energy Commission, whose General Advisory Committee was chaired by Oppenheimer. When Downey was first given the script for Oppenheimer, at Nolan's house, he was surprised to discover the screenplay came on red paper, for security reasons. "I guess there's something about it that makes it that you forget it as soon as you read it," joked Downey. "I don't know what those colors are. Anyway, it's a thing. You read the script, it's written in the first person, you're transported, and it's a journey to read it, and then at the end of that, the guy who wrote the script you just read is asking you if you want to do it. It's kind of like being hypnotized."

Universal Pictures; Library of Congress Florence Pugh in 'Oppenheimer' and the real-life Jean Tatlock

Florence Pugh is Jean Tatlock

Black Widow actress Florence Pugh has the small but vital role of Oppenheimer's troubled lover, the psychiatrist Jean Tatlock (photos of whom are not readily available). "Working with Florence was amazing," said Nolan. "[It was] a very tough role. Very precise, the screen time — short, but so important in Oppenheimer's life."

Melinda Sue Gordon/ Universal Pictures, Bettmann Archive Tom Conti in 'Oppenheimer' and the real Albert Einstein

Tom Conti is Albert Einstein

Scottish actor Tom Conti scored an Oscar nomination portraying an alcoholic poet in 1983's Reuben, Reuben and later appeared on Friends as the father of Emily Mortimer's character. In Oppenheimer, he plays Einstein, the famous physicist and a resident scholar at Princeton's Institute for Advanced Research, where Oppenheimer was director from 1947 to 1966.

Karwai Tang/WireImage, Bettmann Archive David Dastmalchian and the real William Borden

David Dastmalchian is William Borden

David Dastmalchian got his big break when Nolan cast him as Thomas Schiff in 2005's The Dark Knight. Eighteen years on, the Ant-Man and Blade Runner 2049 actor plays Borden, a staff member of Congress' Joint Atomic Energy Committee. "I didn't even think he remembered me," the actor said of Nolan in an interview that took place before the actors' strike. "I didn't even think he would know who I was. It turns out I was wrong, and he gave me an opportunity to come and play in his incredible creative space, with some of the best actors of our time, all of whom treated me so kindly, and welcomed me, and made me feel like I belonged."

Melinda Sue Gordon/ Universal Pictures, Smith Collection/Gado/Getty Josh Hartnett in 'Oppenheimer' and the real-life Ernest Lawrence

Josh Hartnett is Ernest Lawrence

Following his recent appearances in Guy Ritchie's Operation Fortune and on Black Mirror, the Hartnaissance continues with Josh Hartnett's performance as Nobel Prize-winning physicist Ernest Lawrence. According to Downey, the star of The Faculty and Pearl Harbor was "really versed" in physics: "I was picking his brain."

Melinda Sue Gordon/ Universal Pictures, Bettmann Archive Kenneth Branagh in 'Oppenheimer' and the real-life Niels Bohr

Kenneth Branagh is Niels Bohr

Kenneth Branagh, who starred in Nolan's films Dunkirk and Tenet and is, of course, a director and Oscar-winning screenwriter in his own right, plays another Nobel winner, the Danish physicist Niels Bohr, something of a mentor to Oppenheimer and other scientists of his generation.

Universal Pictures/ Youtube, Corbis/Getty David Krumholtz in 'Oppenheimer' and the real-life Isidor Isaac Rabi

David Krumholtz is Isidor Isaac Rabi

Numb3rs star David Krumholtz returns to genius-playing territory as Nobel Laureate Rabi, who befriended Oppenheimer in the '20s when both were traveling in Europe. The physicist later testified on behalf of his pal at the Atomic Energy Commission's 1954 hearing to examine whether Oppenheimer's security clearance should be revoked.

Melinda Sue Gordon/ Universal Pictures, Bettmann Archive Rami Malek in 'Oppenheimer' and the real-life David L. Hill

Rami Malek is David L. Hill

Bohemian Rhapsody Oscar-winner Rami Malek portrays Chicago-based experimental physicist Hill who has a brief but important role to play in the plot of the film. "Rami Malek comes in for one day and it was an absolute mic drop moment," said Downey.

Universal Pictures/ Youtube, Bettmann Archive Benny Safdie in 'Oppenheimer' and the real-life Edward Teller

Benny Safdie is Edward Teller

Uncut Gems co-director Benny Safdie plays Hungarian theoretical physicist Teller, who is best known for his role in the creation of the hydrogen bomb. "Interestingly, Benny Safdie, he had a moment in his life where he was either going to be a physicist or a filmmaker," explained Nolan. "And, I think fortunately for us, he became a filmmaker and went into the world of film and is now acting as well. But he's a very serious physics nerd, he knows a lot. He was very, very busy when I asked him to take on the role of Teller, but I think he just really wanted to do it because of his love of and knowledge of physics."

Dominik Bindl/WireImage, AP Photo Tony Goldwyn and real-life Gordon Gray

Tony Goldwyn is Gordon Gray

Nolan hand-picked veteran movie and TV actor Tony Goldwyn to portray attorney Gray, whose chairing of the Atomic Energy Commission committee examining Oppenheimer's security clearance in the mid-'50s would come to be regarded as a scandal.

Melinda Sue Gordon/ Universal Pictures, AP Photo/John Rous Jason Clarke in 'Oppenheimer' and real-life Roger Robb

Jason Clarke is Roger Robb

Jason Clarke, the Australian star of Zero Dark Thirty and the Pet Sematary remake, portrays the relentless Robb, special counsel to the Atomic Energy Commission who, in Oppenheimer, interrogates many of the movie's main characters including those played by Murphy, Damon, and Blunt. "I was genuinely surprised with Jason Clarke," Damon told EW. "The first time I sat in that room and was cross-examined by him... [he was] intimidating. It was great."

Oppenheimer is in theaters now.

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