Emily Blunt Reveals the "Secret Language" That Connects Her to Cillian Murphy in Oppenheimer

Actor Cillian Murphy may embody the man behind Oppenheimer — physicist J. Robert Oppenheimer — but he's not playing the only Oppenheimer onscreen. Golden Globe Award winner Emily Blunt plays Oppenheimer's wife, Katherine "Kitty" Oppenheimer, a biologist, botanist, and her husband's biggest champion.

This isn't the first time Blunt and Murphy have worked together, either. Their time on A Quiet Place Part II resulted in a friendship and working relationship that Blunt said helped bring the Oppenheimers' often dramatic real-life marriage to the big screen.

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"I adore him as a person," Blunt told NBC Insider of her chemistry with Murphy. "He's a friend — I loved working with him before. We have a lot of trust with each other. And so it does lead to freedom in a scene with somebody when you just have a sort of history with them. It's like a sort of secret language or something.

"And I loved that going into this and walking in the shoes of this rather tempestuous couple that we knew each other," she continued. "So we understood all the nuance of how the other one liked to work but I think the scenes with Cillian because he's so transporting, they always sort of take on a different life than what's on the page and that's why I love working with him so much." 

"Tempestuous" is an apt descriptor for the Oppenheimers' relationship. 

Married in 1940, Robert and Kitty moved to Los Alamos, New Mexico, with their eldest child Peter and the families of other scientists who were participating in the Manhattan Project. Their second child, Toni, was born in Los Alamos at the local hospital, which the Atomic Heritage Foundation explains was known as the “RFD,” for “rural free delivery” due to the high number of births that occurred within the Project’s first few years.

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During her time in Los Alamos, Kitty suffered from isolation and addiction, which resulted in friction in her marriage. Additionally, Robert carried on a years-long affair with psychiatrist Jean Tatlock (portrayed by Florence Pugh in the film), which served as a stressor in his relationship with his wife.

All this and more will be shown in Oppenheimer when it premieres exclusively in theaters on July 21.

Reporting by Stephanie Gomulka.