Christopher Nolan’s latest film, Oppenheimer, tells the story of physicist and head of the Manhattan Project’s secret weapons lab, J. Robert Oppenheimer, portrayed by longtime Nolan collaborator Cillian Murphy. To tell this harrowing recount, Nolan employed the talent of an impressive lineup of stars, including Oscar-winner Matt Damon and Emily Blunt, who sat down with Collider’s Steve Weintraub to talk about their experience on set and the opportunity to “be a part of a film that is lasting.”

In the movie, Damon, who previously worked with the director on 2014’s Interstellar, plays the role of General Leslie Groves Jr., the director of the Manhattan Project and the man who appointed Oppenheimer to oversee the creation of the world’s first atomic bomb. Blunt plays Katherine “Kitty” Oppenheimer, a fellow scientist and Robert’s wife, who provided the physicist with what advice she could and a safe haven from the weight of his assignment. As were their real-life counterparts, Damon tells Weintraub their job, according to Nolan, was to provide the necessary support Murphy needed, considering this unique script “hinges on that performance.” They go on to discuss the impact of the movie, admitting, “It’s hard to stop talking about.” Joining them on the roster are Robert Downey Jr., Florence Pugh, Gary Oldman, and David Dastmalchian.

During their conversation, which you can watch or read below, Damon and Blunt describe what it’s like to work with IMAX cameras and how cinematographer Hoyte Van Hoytema plays a part in making the process effortless. They also reveal Nolan’s “convenient casting” method, what it was like to read the script for the first time in the filmmaker’s living room, and why audiences should try to catch one of the limited IMAX 70mm screenings.

COLLIDER: I’m going to start with the most important question upfront; when Universal and Chris Nolan came to you and said, “We want to make a sequel to The Adjustment Bureau, but we want to call it Oppenheimer, and it’s going to be about Robert Oppenheimer, but it’s really a sequel to The Adjustment Bureau…”

EMILY BLUNT: We were like, “Wait, you can’t go through doors in Oppenheimer with your fedora?” You didn’t wear a fedora in this.

MATT DAMON: I didn’t.

BLUNT: He did.

DAMON: [Laughs] He did, he wore the fedora.

Image via Universal Pictures

[Laughs] So I’m a fan of both of your works, and there are going to be a lot of people out there who have actually never seen anything you’ve done before. For someone who’s never seen anything, what’s the first thing you’d like them to watch and why?

DAMON: Oppenheimer. Really. It’s the biggest story of our lives, maybe in the history of the human species so far, told by a director who’s at the absolute top of his game, with one of the great screen performances at the center of it. Chris always said to us when we were making it, “I need you guys in support.” That’s the mission, basically, is supporting Cillian [Murphy]. This whole movie hinges on that performance. It’ll resonate emotionally if we’re with that character. He wrote the script in the first-person, which I’d never seen before. So, instead of saying, “Oppenheimer walked across the room,” it’s, “I walk across the room.” It just ripped you into that world, and given what’s at stake, there’s not a more important story out there.

BLUNT: Agreed! Agreed. [Laughs]

DAMON: [Laughs] You can answer the next question.

BLUNT: What’s your next question?

You guys obviously read a lot of scripts and you get offered a lot of roles, what is it like when Chris calls or texts you?

BLUNT: You just say, “Whatever you want. Whatever you need. Do you need me to say a line? Do you want me to do catering?” Like, “What do you need from me?” It’s so pulsating when you know he wants to meet you. It’s the best feeling ever because he’s so extraordinary, he’s of such vast talent and ability, you know you’re going to be a part of a film that is lasting. In whatever capacity that is. So, I was thrilled to meet him. He’s just a cool guy, as well. We talked for hours even before he gave me the script. I went to his living room and I read the script, then we talked more afterwards. I think that’s what I love most about him, the curiosity in the process, the passion for it, the passion for actors and what you need, and to take away all the chaos from you even though I’m sure to keep all the plates in the air of shooting a film of this scale, he must have had endless plates in the air. He must have had a hurricane going on inside of him throughout the whole process.

DAMON: But you just don’t feel that.

BLUNT: You don’t feel it. You feel this focus, this beautiful masterclass, all the time.

DAMON: Because he wants to create an environment, even at that scale of storytelling, where you’re free creatively to come up with your best ideas and to put them out there. There’s no rigidity. You would think, with that much going on, that he would say, “Say your line here and cross over to there,” and there’s none of that.

BLUNT: My favorite is how English he is when he’s happy.

DAMON: [Laughs] Yeah.

BLUNT: It’s my favorite. He’s like, “Yeah, good. Happy? Okay, moving on. Let’s go.” And you’re just like, “Was it good?”

DAMON: That’s Chris at his happiest, by the way. You know the scene went well.

Image via Universal

You mentioned already how you read the script in his living room, and I know he asks people to come to his house to read the script, so what is it like for you sitting in his house, reading the script, knowing he’s in the other room waiting for you to finish?

DAMON: In my case, he actually came—this is kind of a funny story—he came to my apartment here in New York, and I live in the same apartment building as Emily. So he came because he had personal reasons to be in New York, so he goes, “I’m going to come over, and I’m going to bring you the script.” I said, “Great.” So, he comes over and we talk. It’s a Friday night, it’s getting late, and he says, “So you’re going to read this tomorrow morning?” I said, “Yes.” He said, “What time?” And I said, “I’ll read it at nine.” He said, “How long will it take you?” I go, “I read it exactly at the same pace the movie will play.” He goes, “I’ll be here at noon.” I said, “Okay.”

So it turns out, we came to find out later, that he knew he wanted Emily in that part and me in my part, but he didn’t want to offer her the part at the same apartment building on the same day because he didn’t want it to seem to us like he only just went to one apartment building to cast his movie. [Laughs]

BLUNT: Convenient casting. “Who else lives here?” [Laughs]

DAMON: So he pretended that he didn’t– Then he called her a few days later and said, “Oh, would you like to–?” Because she happened to be in LA on business. “Would you like to come over and read this script?” It was very funny.

BLUNT: I think I was probably nervous reading it at first, thinking, “Am I going to be behind the physics and the science? Am I going to be able to wrap my head around all of it?” Then you realize, that is the backdrop. That is not the full thrust of the script. That’s not what’s so pulsating about it. It was such an emotional script to read. It’s really about the trauma of living with a brain like that and the ramifications of what that brain brought to the world.

But I knew he would come in. The worst thing is when you read a script and you have to perform your love of it. There’s none of that with Chris. Nothing’s performative, ever, because what he creates is so extraordinary. So he came in, and I said, “My heart’s racing,” I said, “I feel like my whole body’s on fire reading this script.” And you don’t have to perform it because it is.

Image via Universal Pictures

I saw the film last night in IMAX 70mm at the Lincoln Square Theater. There are no words for that presentation. Have you guys seen it in IMAX 70?

DAMON: Oh yeah, yeah.

BLUNT: Yes.

Can you watch yourselves on screen, or do you get a little tweaked out by it?

BLUNT: Sometimes I do if I think the film’s not very good, but I felt this was a full kidnap, this one. I thought my bones were going to shatter. I felt this weight on my breastplate the whole way through it. You feel like you’re inside of it. I think we were all at a loss for words afterwards. It was emotional. I watched it with Robert [Downey Jr.], and we were both really emotional watching it.

DAMON: I had spoken to Emily because she saw it before I did, so I was kind of prepared for that. I didn’t think about watching myself on it.

BLUNT: We couldn’t stop talking to you about it, could we? We just went on and on.

DAMON: It’s hard to stop talking about. It’s really something.

Completely. The shame is that it’s only 30-something theaters around the world that can show it in IMAX 70. For the people watching this, for the love of god…

BLUNT: Please go see it in IMAX. He sweat bullets to make it in IMAX, so go see it.

DAMON: They invented black and white IMAX film for the movie.

BLUNT: For this movie.

100%. I specifically want to ask about working with the IMAX cameras. What is it like when you’re next to one of these? It’s a beast of a camera.

DAMON: It’s big.

BLUNT: They’re big, yeah.

It’s a ton of noise. What is it like actually working with one of those? It’s so expensive for every shot.

DAMON: Yeah, but you’re kind of insulated from that side of it. I’m sure Emma [Thomas], as a producer, is probably much more aware of that than the actors are. At the beginning of my career, movie cameras were quite big, and I remember in my teens and early 20s having to think about technically trying to assimilate that into my process. Then everything kind of got easier. The light, if you’re working on [digital]—which Chris never does—they’re much more light sensitive, so there’s less gear now, but in general, there’s less gear. Going back to IMAX, it felt like the beginning of my career. It doesn’t feel obtrusive.

Image via Universal Pictures

BLUNT: It’s more that they’re really, really loud. You just know it’s not going to be a take where they use the sound that you did. Chris will then sort of pre-record, and he’ll use a different take where you can use the same dialogue within the IMAX frame as well. He tries to do everything in-camera. You don’t want to be ADR-ing stuff. But I think you get that sense because Hoyte [Van Hoytema], I don’t know how he slings that IMAX camera on his shoulder without breaking his back, but he does. And because Hoyte is so sensitive to the process, you stop noticing him. You don’t notice Chris, who’s a big guy.

DAMON: And he’s always standing right next to the camera.

BLUNT: And watching you.

DAMON: The way the old-school– It’s what [Francis Ford] Coppola told me years ago, he said that’s what Antonio said to him. He said, “You sit next to your operator and you look at it with your naked eye…”

BLUNT: But you don’t notice them, do you?

DAMON: You don’t notice them at all.

BLUNT: They sort of disappear in some ways because there’s so much focus.

DAMON: But also, they’re kind of with you. You’re kind of there in a group talking anyway, and then suddenly Hoyte’s got the camera on his– You know what I mean? It feels so intimate even though it’s at this massive scale. They somehow manage to make it feel so relaxed. It’s really something.

Oppenheimer opens in theaters and IMAX on July 21. You can check out Collider’s interview with Christopher Nolan below.