Cillian Murphy reacted to Oppenheimer costar Matt Damon’s revelation that he did not like to socialize like the rest of the cast — and the Oscar nominee explained why.

Oppenheimer was shot in a remote New Mexico desert that had one hotel and one restaurant. Damon, 53, who costarred in the film as General Leslie Groves, said the cast members would always eat together. However, because Murphy, 47, was so focused on his character, he was extremely distant when they socialized and often turned down dinner invitations.

During a 60 Minutes interview broadcast on Sunday, February 18, host Scott Pelly shared Damon’s observation with Murphy, 47.

“Matt Damon told me that ‘Cillian is the worst dinner companion imaginable,’” Pelley, 66, said. “What he meant by that was when you’re working on a film — when you’re being the character — there’s very little room in your head for anything else.”

Related: Cillian Murphy’s Wildest Quotes About Playing Oppenheimer

Cillian Murphy shocked fans with his thrilling performance in Oppenheimer — but many people don’t know the extreme preparation he went through to prepare for the role. “[Murphy] had such a monumental undertaking,” Murphy’s costar Emily Blunt told Extra in July 2023. “And he could only eat, like, an almond every day. He was so […]

Murphy agreed that he was not very sociable during filming.

“Yeah, I mean, I’ve always been like that, I think,” he responded, laughing. “But it’s because, to me, you have the time on set, which is short enough time — you have 10 hours, maybe. And then the other part, if you’ve got a significant part, you’re having to keep your lines fresh.”

When he wasn’t focused on the script, Murphy quipped that he was interested in getting some shut eye.

“The other big thing for me is sleeping. I love sleeping and I need sleep,” he continued. “You just don’t have the room … in your head, and you want as much sleep as possible.”

Matt Damon says, “Cillian is the worst dinner companion imaginable.” Hear Cillian Murphy’s reaction. https://t.co/FNkS0GJWQC pic.twitter.com/a2UkC9xlNF

— 60 Minutes (@60Minutes) February 19, 2024

Murphy added that once production ended, he was much more fun to be with.

“I’ve had lots of lovely dinners with Matt Damon since the movie’s finished and we’ve been out promoting it and stuff.”

In a separate interview with Entertainment Tonight in July 2023, Damon said he understood why Murphy did not join the cast for meals.

“He was losing so much weight for the role that he couldn’t eat dinner,” he explained, adding that Murphy noshed on “one almond most nights or a little slice of apple.”

Related: Cillian Murphy Through the Years: A Look at the Irish Actor’s Career

Cillian Murphy honed his craft for nearly three decades before his Oppenheimer role made him one of Hollywood’s biggest names. “I’m stubborn and lacking in confidence, which is a terrible combination,” Murphy joked to The Guardian in July 2023 while promoting the project. He confessed: “I don’t want to put anything out that I don’t […]

Emily Blunt, who starred as Oppenheimer’s wife, Katherine “Kitty” Oppenheimer, told ET that Murphy needed time alone after shooting to prepare for his very demanding character

“The sheer volume of what [Murphy] had to take on [for the role] and shoulder is so monumental,” she said. “Of course, he didn’t want to come and have dinner with us.”

Robert Downey Jr., who portrayed Atomic Energy Commission chairman Lewis Strauss, told People that he was in awe of Murphy’s performance.

“I have never witnessed a greater sacrifice by a lead actor in my career,” Downey, 58, said in a July 2023 interview. “He knew it was going to be a behemoth ask when Chris [director Christopher Nolan] called him. But I think he also had the humility that is required to survive playing a role like this.”