Oppenheimer is one of the biggest box office hits of 2023, and it's also one of the darkest. The Christopher Nolan-directed epic centers around J. Robert Oppenheimer's efforts to build the atomic bomb during World War II, and faces the consequences. The film deals with intense themes like unchecked bureaucracy, morality in the face of war and power structures that lead to destruction. Given that a lot is needed to be able to fully capture the complexities of the protagonist and intricacies of the plot, a lot was expected of Cillian Murphy, who plays the eponymous character. According to the Peaky Blinders star, one "rule" had to be instituted on set for him to go to the dark places necessary for the character and, thankfully, co-star Emily Blunt was able to help make it happen.
Amid awards season, Cillian Murphy was profiled by the L.A. Times, and he opened up about what went into his Oscar-worthy performance in Oppenheimer. Additionally, he spoke about how his co-stars created levity on set, which allowed him to relax. While some actors like a somber environment to get into the mind of their character, Murphy said that he relies on a high-spirited energy to fully be able to explore his role. He explained how Emily Blunt helped with this, saying:
