Oppenheimer: Christopher Nolan Let One Actor Improvise Shocking Line

Oppenheimer has become a bonafide hit, earning the best box office performance yet for a Christopher Nolan-helmed film. The three-hour epic brings to life the true story of J. Robert Oppenheimer (Cillian Murphy) and those who were in his orbit during and after the creation of the atomic bomb — and apparently, one of the darkest scenes was expanded upon while filming. In a recent profile with The New York Times, Nolan revealed that the line from Henry Stimson (James Remar) about choosing not to bomb the part of Japan that he honeymooned in was added at the last minute. This came after Remar himself researched the intricacies of Stimson's life, a bit of homework that many of Oppenheimer's ensemble cast members did with their characters.

"There's a moment where James Remar… He kept talking to me about how he learned that Stimson and his wife had honeymooned in Kyoto," Nolan said. "That was one of the reasons that Stimson took Kyoto off the list to be bombed. I had him crossing the city off the list because of its cultural significance, but I'm like, 'Just add that.' It's a fantastically exciting moment where no one in the room knows how to react."

"Each actor was coming to the table with research about what their real-life counterpart had been," Nolan said earlier in the interview. "They had tons of homework to do. They had a great resource with 'American Prometheus.' They then did their own research and what it meant for me, which isn't something I'd ever really been able to do in the past. So, for example, with the scene in the section classroom with all the scientists, we would be able to improvise the discussion. The script is there, but they could come into it with passion and knowledge based on all of their own learning."

What Is Oppenheimer About?

Oppenheimer follows the life of theoretical physicist J. Robert Oppenheimer, the director of the Los Alamos Laboratory during the Manhattan Project, and his contributions that led to the creation of the atomic bomb.

The film stars Cillian Murphy as J. Robert Oppenheimer, Emily Blunt as Katherine "Kitty" Oppenheimer, Matt Damon as Leslie Groves, Robert Downey Jr. as Lewis Strauss, Florence Pugh as Jean Tatlock, Benny Safdie as Edward Teller, Michael Angarano as Robert Serber, Josh Hartnett as Ernest Lawrence, Dylan Arnold as Frank Oppenheimer, David Krumholtz as Isidor Isaac Rabi, Matthew Modine as Vannevar Bush, Josh Peck as Kenneth Bainbridge, Devon Bostick as Seth Neddermeyer, Matthias Schweighöfer as Werner Heisenberg, Christopher Denham as Klaus Fuchs, Guy Burnet as George Eltenton, Danny Deferrari as Enrico Fermi, Emma Dumont as Jackie Oppenheimer, Gustaf Skarsgård as Hans Bethe, Trond Fausa Aurvåg as George Kistiakowsky, and Gary Oldman as Harry S. Truman.

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Oppenheimer is now playing exclusively in theaters.