Cillian Murphy/J. Robert Oppenheimer.Photo:Universal Pictures; Bettmann Archive/Getty

Universal Pictures; Bettmann Archive/Getty
Oppenheimeris already one of 2023’s most explosive films, thanks to its remarkableensemble cast.
Christopher Nolan’s highly anticipated war drama revisits the pivotal development of the atomic bomb and depicts all the people who had a hand in the history-making. Nolan has previously spoken about theweighty taskof directing J. Robert Oppenheimer’s biopic.
“It’s a story of immense scope and scale,” Nolan toldTotal Filmin December 2022. “And one of the most challenging projects I’ve ever taken on in terms of the scale of it, and in terms of encountering the breadth of Oppenheimer’s story.”
01of 12Cillian Murphy as J. Robert OppenheimerCillian Murphy/J. Robert Oppenheimer.Universal Pictures; Bettmann Archive/GettyCillian Murphyplays the titular theoretical physicist inChristopher Nolan’s long-awaited flick. Speaking to theAssociated Pressback in May,Murphy opened upabout playing the man remembered as the “father of the atomic bomb.” He called the role “a huge responsibility” since Oppenheimer “was complicated and contradictory and so iconic.“Murphy enduredphysical and mental challengesas he prepared for the part. He toldTheNew York Timesabout how he lost “quite a bit of weight” to appear as Oppenheimer did. “He was very slim,” said the Irish actor. “Almost emaciated.“In conversation withThe Guardian, Murphy explained that his extreme diet affected his behavior, too. “I was running on crazy energy; I went over a threshold to where I was not worrying about food or anything,” he said. “I was so in it, a state of hyper something. But it was good because the character was like that. He never ate.”
01of 12
Cillian Murphy as J. Robert Oppenheimer
Cillian Murphy/J. Robert Oppenheimer.Universal Pictures; Bettmann Archive/Getty

Cillian Murphyplays the titular theoretical physicist inChristopher Nolan’s long-awaited flick. Speaking to theAssociated Pressback in May,Murphy opened upabout playing the man remembered as the “father of the atomic bomb.” He called the role “a huge responsibility” since Oppenheimer “was complicated and contradictory and so iconic.”
Murphy enduredphysical and mental challengesas he prepared for the part. He toldTheNew York Timesabout how he lost “quite a bit of weight” to appear as Oppenheimer did. “He was very slim,” said the Irish actor. “Almost emaciated.”
In conversation withThe Guardian, Murphy explained that his extreme diet affected his behavior, too. “I was running on crazy energy; I went over a threshold to where I was not worrying about food or anything,” he said. “I was so in it, a state of hyper something. But it was good because the character was like that. He never ate.”
02of 12
Emily Blunt as Katherine “Kitty” Oppenheimer
Emily Blunt - Kitty Oppenheimer.Universal Pictures; CORBIS/Corbis via Getty

Universal Pictures; CORBIS/Corbis via Getty
Blunt spoke to PEOPLE abouther relationship with her on-screen husbandjust a month before the film’s premiere in mid-July.
“Me and Cillian are like thick as thieves because we worked together before [onA Quiet Place Part II] and I adore him,” she said. “We have a lot of trust between us. So I spent the most time with Cillian.”
03of 12Matt Damon as Leslie GrovesMatt Damon/Leslie Groves.Universal Pictures ; MPI/GettyMatt Damonplays Lieutenant General Leslie Groves in the historical drama. During World War II, the Army Corps of Engineers officer worked on the Pentagon’s construction before directing the Manhattan Project.Damon recentlyexpressed his excitementabout working with Christopher Nolan again in an interview withEntertainment Weekly, and how his passion for the director cuts deep into his personal life. Damon shared that he promised his wife, Luciana, that he’d take time off workunlessNolan offered him a role.“This is without knowing whether or not he was working on anything, because he never tells you,” added the actor, who also appeared in Nolan’s 2014 space dramaInterstellar. “He just calls you out of the blue. And so, it was a moment in my household.”
03of 12
Matt Damon as Leslie Groves
Matt Damon/Leslie Groves.Universal Pictures ; MPI/Getty

Universal Pictures ; MPI/Getty
Matt Damonplays Lieutenant General Leslie Groves in the historical drama. During World War II, the Army Corps of Engineers officer worked on the Pentagon’s construction before directing the Manhattan Project.
Damon recentlyexpressed his excitementabout working with Christopher Nolan again in an interview withEntertainment Weekly, and how his passion for the director cuts deep into his personal life. Damon shared that he promised his wife, Luciana, that he’d take time off workunlessNolan offered him a role.
“This is without knowing whether or not he was working on anything, because he never tells you,” added the actor, who also appeared in Nolan’s 2014 space dramaInterstellar. “He just calls you out of the blue. And so, it was a moment in my household.”
04of 12
Robert Downey Jr. as Lewis Strauss
Robert Downey Jr./Lewis Strauss.Universal Pictures; Pictorial Parade/Archive Photos/Getty

Universal Pictures; Pictorial Parade/Archive Photos/Getty
While Downey’s character had more than a few qualms about Oppenheimer’s story, the actor himself feels the complete opposite.Deadlineshared a video of the starpraising the filmat its London premiere.
“Just going to flat out say it: This is the best film I’ve ever been in,” Downey says in theclip. “I cannot wait for you all to experience it.”
05of 12Florence Pugh as Jean TatlockFlorence Pugh/Jean Tatlock.Universal Pictures;Florence Pughplays Oppenheimer’s mistress, Jean Tatlock. Her associations with the Communist Party placed the physicist in a precarious position during the investigations of his political affiliations.TheMidsommaractress alsoexpressed her appreciationfor Nolan’s casting her in the film. Pugh complimented his directing approach while speaking to the Radio Times.“When I walked on set, I couldn’t believe there was that similar, incredible adrenaline, which I hadn’t felt on a massive movie for a long time,” she said. “It’s a wonderful thing to inject into a film set — believing in yourself and what you’re making.”
05of 12
Florence Pugh as Jean Tatlock
Florence Pugh/Jean Tatlock.Universal Pictures;

Universal Pictures;
Florence Pughplays Oppenheimer’s mistress, Jean Tatlock. Her associations with the Communist Party placed the physicist in a precarious position during the investigations of his political affiliations.
TheMidsommaractress alsoexpressed her appreciationfor Nolan’s casting her in the film. Pugh complimented his directing approach while speaking to the Radio Times.
“When I walked on set, I couldn’t believe there was that similar, incredible adrenaline, which I hadn’t felt on a massive movie for a long time,” she said. “It’s a wonderful thing to inject into a film set — believing in yourself and what you’re making.”
06of 12Josh Hartnett as Ernest LawrenceJosh Hartnett/Ernest Lawrence.Universal Pictures; Smith Collection/Gado/GettyThe war drama featuresJosh Hartnettas Ernest Lawrence, a Nobel Prize-winning physicist who played a key role in the Manhattan Project.
06of 12
Josh Hartnett as Ernest Lawrence
Josh Hartnett/Ernest Lawrence.Universal Pictures; Smith Collection/Gado/Getty

Universal Pictures; Smith Collection/Gado/Getty
The war drama featuresJosh Hartnettas Ernest Lawrence, a Nobel Prize-winning physicist who played a key role in the Manhattan Project.
07of 12Casey Affleck as Boris PashCasey Affleck/Boris Pash.Lionel Hahn/Getty; Alamy Stock PhotoCasey Affleckplays a military intelligence officer tasked with interrogating Oppenheimer and others about their possible affiliations with the Communist Party. Boris Pash eventually concluded that the Manhattan Project leader wasn’t a spy, and should remain a part of the nuclear development efforts.
07of 12
Casey Affleck as Boris Pash
Casey Affleck/Boris Pash.Lionel Hahn/Getty; Alamy Stock Photo

Lionel Hahn/Getty; Alamy Stock Photo
Casey Affleckplays a military intelligence officer tasked with interrogating Oppenheimer and others about their possible affiliations with the Communist Party. Boris Pash eventually concluded that the Manhattan Project leader wasn’t a spy, and should remain a part of the nuclear development efforts.
08of 12Kenneth Branagh as Niels BohrKenneth Branagh/Niels Bohr.Samir Hussein/WireImage; Gado/GettyKenneth Branaghplays one of quantum physics' most foundational minds, Niels Bohr. During World War II, Bohr supported the efforts of Robert Oppenheimer and his colleagues working on the Manhattan Project. Bohr was a promoter of scientific progress and his hopes for nuclear development aligned with Oppenheimer’s, despite the impact both knew it would have on international affairs.
08of 12
Kenneth Branagh as Niels Bohr
Kenneth Branagh/Niels Bohr.Samir Hussein/WireImage; Gado/Getty

Samir Hussein/WireImage; Gado/Getty
Kenneth Branaghplays one of quantum physics' most foundational minds, Niels Bohr. During World War II, Bohr supported the efforts of Robert Oppenheimer and his colleagues working on the Manhattan Project. Bohr was a promoter of scientific progress and his hopes for nuclear development aligned with Oppenheimer’s, despite the impact both knew it would have on international affairs.
09of 12
Benny Safdie as Edward Teller
Benny Safdie/Edward Teller.Universal Pictures.; Slim Aarons/Getty

Universal Pictures.; Slim Aarons/Getty
Safdie’sOppenheimerrole is his biggest to date. Speaking toGQ, Nolan said that he cast the actor after seeing him inGood Time(which Safdie directed with his brother) and in Paul Thomas Anderson’s 2021 indie film,Licorice Pizza.
“I called Paul [Thomas Anderson] and I asked about Benny,” Nolan recalled. “And he gave him the strongest possible endorsement and pointed out that he’s an incredible actor, but also just a wonderful guy.”
10of 12Dylan Arnold as Frank OppenheimerDylan Arnold as Frank Oppenheimer.Universal Pictures; gettyFans will probably recognize Arnold as Love Quinn’s boy toy in Netflix’sYouand the actor continues to flex his drama skills playing Frank Oppenheimer in the Nolan epic.Much like his older brother, Frank was atalented scientistwho earned a degree in physics from Johns Hopkins University before later getting his Ph.D. from the California Institute of Technology, where he studied artificially induced radiation.He joined the Manhattan Project in 1945 and became a professor after the war. A devout lover of science, Frank founded the Exploratorium — a museum of science, technology and arts — in 1969.
10of 12
Dylan Arnold as Frank Oppenheimer
Dylan Arnold as Frank Oppenheimer.Universal Pictures; getty

Universal Pictures; getty
Fans will probably recognize Arnold as Love Quinn’s boy toy in Netflix’sYouand the actor continues to flex his drama skills playing Frank Oppenheimer in the Nolan epic.
Much like his older brother, Frank was atalented scientistwho earned a degree in physics from Johns Hopkins University before later getting his Ph.D. from the California Institute of Technology, where he studied artificially induced radiation.
He joined the Manhattan Project in 1945 and became a professor after the war. A devout lover of science, Frank founded the Exploratorium — a museum of science, technology and arts — in 1969.
11of 12Gary Oldman as President Harry S. TrumanGary Oldman as President Truman.Matt Winkelmeyer/Getty; gettyGary Oldman and Christopher Nolan reunite once more. Because the two haven’t worked together since they collaborated on theBatmantrilogy, fans were excited to hear they’re working together again, though Oldman appears in only one scene in the film.The veteran actor plays President Truman, who ordered the atomic bomb be used in the bombings of Hiroshima and Nagasaki during WWII.
11of 12
Gary Oldman as President Harry S. Truman
Gary Oldman as President Truman.Matt Winkelmeyer/Getty; getty

Matt Winkelmeyer/Getty; getty
Gary Oldman and Christopher Nolan reunite once more. Because the two haven’t worked together since they collaborated on theBatmantrilogy, fans were excited to hear they’re working together again, though Oldman appears in only one scene in the film.
The veteran actor plays President Truman, who ordered the atomic bomb be used in the bombings of Hiroshima and Nagasaki during WWII.
12of 12Jason Clarke as Roger RobbJason Clarke as Roger Robb.Melinda Sue Gordon/ Universal Pictures, AP Photo/John RousPlaying U.S. attorney Roger Robb is Jason Clarke. Robb was selected to prosecute Oppenheimer’s security clearance hearing in 1954.“What I was reminded of with the whole story of [Oppenheimer] … is that we really don’t know all of the benefits and the cost of what this man, this group and his leadership have done for this planet,” Clarke reflected while at theParis premiere of the film. “The story is still going to play out. I truly believe that.”
12of 12
Jason Clarke as Roger Robb
Jason Clarke as Roger Robb.Melinda Sue Gordon/ Universal Pictures, AP Photo/John Rous

Melinda Sue Gordon/ Universal Pictures, AP Photo/John Rous
Playing U.S. attorney Roger Robb is Jason Clarke. Robb was selected to prosecute Oppenheimer’s security clearance hearing in 1954.
“What I was reminded of with the whole story of [Oppenheimer] … is that we really don’t know all of the benefits and the cost of what this man, this group and his leadership have done for this planet,” Clarke reflected while at theParis premiere of the film. “The story is still going to play out. I truly believe that.”
source: people.com