Emily Blunt Jokes About Being Distracted by Cillian Murphy’s ‘Ocean Eyes’ on ‘Oppenheimer’ Set

“Sometimes you find yourself just swimming in his eyes,” adds Matt Damon of his costar

The A-list cast of Christopher Nolan’s A-bomb epic Oppenheimer all agree the film’s star, Irish actor Cillian Murphy, gives the performance of his life as J. Robert Oppenheimer, the American physicist who led the U.S. effort to create an atomic bomb during World War II.

But they also agree that his deep-blue eyes can be distracting when acting opposite him.

“It’s a real problem when you’re doing scene work with Cillian,” Matt Damon, 52, tells PEOPLE in this week’s issue, in a group interview alongside Emily Blunt and Murphy. The Oscar winner plays the director of Oppenheimer’s Manhattan Project, Gen. Leslie Groves. “Sometimes you find yourself just swimming in his eyes,” he says.

Blunt, 40, who plays Oppenheimer’s troubled wife, Kitty, meanwhile jokes: “It’s like that ‘Ocean Eyes’ song by Billie Eilish. We just hum it all day.”

Christopher Nolan’s ‘Oppenheimer’: Everything to Know

“They’re not even that blue!” exclaims Murphy, 47, in response to his costars’ comments.

In the group interview, Blunt equated filming the movie with the sprawling cast in New Mexico to being at “summer camp.”

“We were all in the same hotel in the middle of the New Mexican desert,” she recalls. “We only had each other. Me and Matt were roommates and we were like, ‘Let’s go to have dinner.’ “

Sadly for Murphy, he rarely got to join in on the fun due to the daunting task of leading Nolan’s film.

“The sheer volume of what he had to take on and shoulder is so monumental,” marvels Blunt. “Of course he didn’t want to come and have dinner with us.” Damon agrees, saying, “He couldn’t. His brain was just too full.”

Adds Murphy, “You know that when you have those big roles, that responsibility, you feel it’s kind of overwhelming.”