Cillian Murphy missed out on a key opportunity to bond with his castmates while not filming their new movie Oppenheimer.

The 47-year-old Peaky Blinders actor – who brings J. Robert Oppenheimer, the “father of the atomic bomb” to life – skipped out on group dinners with co-stars including Matt Damon and Emily Blunt.

During a recent interview, they explained why he wasn’t involved in moment that they compared to summer camp experiences.

Read more about why Cillian Murphy wasn’t involved with cast dinners…

Speaking to People, Emily said that filming together in the middle of the desert made it easier for the cast to bond. That included grabbing dinner together. However, she added that Cillian wasn’t able to join them due to the stress of his role.

“The sheer volume of what he had to take on and shoulder is so monumental,” she said. “Of course he didn’t want to come and have dinner with us.” Matt took it a step further saying that he “couldn’t” join them for meals.”

Why? “His brain was just too full.”

Cillian seemingly agreed, saying, “You know that when you have those big roles, that responsibility, you feel it’s kind of overwhelming.”

Oppenheimer premieres in theaters on July 21, the same day as Barbie. Let us know which movie you’re more excited to see!