Warning: This article contains spoilers for Oppenheimer.

Prior to the start of the SAG-AFTRA strike, the cast of Oppenheimer was extremely active in publicizing writer-director Christopher Nolan's new biopic of J. Robert Oppenheimer, the so-called "father of the atomic bomb." Stars Cillian Murphy, Emily Blunt, Matt Damon, and Robert Downey Jr. undertook a slew of promotional appearances (including EW's Around the Table). That quartet was joined at the film's London premiere, or at least its start, by Florence Pugh, Josh Hartnett, Kenneth Branagh, Rami Malek, and Tom Conti.

There is one notable Oppenheimer actor, however, who did not walk the red carpet in London and whose name was mostly absent from the pre-release hoopla: Gary Oldman. The Darkest Hour Oscar winner plays President Truman, the man who was ultimately responsible for dropping the atomic bombs on Hiroshima and Nagasaki. In the film, Oldman appears in just one — albeit very memorable — scene where the commander-in-chief has an uneasy encounter at the White House with Murphy's Oppenheimer, who is clearly guilt-stricken about the loss of life caused by the weapons that he played a huge role in developing.

While Nolan clearly intended Oldman's appearance in the movie to be a surprise, it is no shock that the director should reteam with the actor. The filmmaker has no problem casting the same actor in different roles. Nolan cast Murphy in five films prior to Oppenheimer and Michael Caine has appeared in eight movies by the director, including Interstellar, whose cast also featured Damon. Oldman, of course, previously worked with Nolan on the director's trilogy of Batman tales, portraying Gotham police chief Jim Gordon in 2005's Batman Begins, 2008's The Dark Knight, and 2012's The Dark Knight Rises.

While participating in EW's Around the Table, Murphy confirmed that Oldman appears in the movie, though not which character he plays in the film. "For me, every day, I was working with the best actors in the world, every single day, and you'd look at the call sheet and there'd be, like, Gary Oldman one day, and then Ken Branagh, and then these guys," said the 28 Days Later star, indicating Blunt, Damon, and Downey. "It was very hard to be cynical when you're working with that level of talent."

Oppenheimer is based on Kai Bird and Martin J. Sherwin's book American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer which details the October 1945, encounter between the pair's subject and Truman. According to the authors, Oppenheimer told the President that he felt he had "blood on my hands," which angered the commander-in-chief. Truman later told his Secretary of State Dean Acheson, "I don't want to see that son-of-a-bitch in this office ever again." (The line is slightly modified in the movie.)

Oppenheimer is in theaters now. See Nolan and his cast reveal more about the making of Oppenheimer in the full Around the Table video above.

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