As fate would have it, Nolan did call with an offer for Damon to star in Oppenhemer.

“This is going to sound made up, but it’s actually true,” Damon said. “I had — not to get too personal — negotiated extensively with my wife that I was taking time off. I had been in ‘Interstellar’ and then Chris put me on ice for a couple of movies, so I wasn’t in the rotation, but I actually negotiated in couples therapy ­— this is a true story — the one caveat to my taking time off was if Chris Nolan called. This is without knowing whether or not he was working on anything, because he never tells you. He just calls you out of the blue. And so, it was a moment in my household.”

Nolan called Damon to offer him the role of Leslie Groves, who was the director of the Manhattan Project. Groves chose Los Alamos, N.M. as one of several testing sites for the development of the atomic bomb. He also personally recruited J. Robert Oppenheimer (played by Cillian Murphy) to lead the charge at Los Alamos — a divisive choice at the time as Oppenheimer lacked a Nobel Prize and administrative leadership experience.

Murphy got his own unexpected call from Nolan with an offer to play the lead role.

“He’s so understated and self-deprecating and, in his very English manner, just said, ‘Listen, I’ve written this script, it’s about Oppenheimer. I’d like you to be my Oppenheimer,’” Murphy told Associated Press earlier this year. “It was a great day… We have this long-standing understanding and trust and shorthand and respect. It felt like the right time to take on a bigger responsibility. And it just so happened that it was a huge one.”

Oppenheimer opens in theaters nationwide July 21 from Universal Pictures.