Photo: Stuart C. Wilson/Getty Images

1917 seems like a straightforward enough pitch: During World War I, two young British soldiers must cross the front line into enemy territory to warn another company that it is walking into an attack. It’s a movie that seems — all apologies to Ford v Ferrari, which has already claimed this throne — engineered to be a Dad Movie. Instead, it’s a sparse script, a thrillingly one-shot epic, tense but with a beating heart: 1,600 lives hang in the balance of this mission, a number both soldiers — the hardened, pragmatic Lance Corporal Schofield (George MacKay) and the cherubic Lance Corporal Blake (Dean-Charles Chapman) — carry with them across the front lines like the rest of their gear.

“We basically just built the film layer by layer,” MacKay says of the war epic. “[Director] Sam Mendes and Krysty Wilson-Cairns had written this beautiful script. But beyond that, we had nothing.” Over six months of rehearsal, and a day-delayed start, the cast and crew mapped the characters’ movements and paced the dialogue to achieve a kind of thrilling, dramatic rhythm. “We had to find the places where this story could take place, these locations. And then we needed to build everything from scratch.” MacKay talked to Vulture about training as a soldier, shooting with Roger Deakins, and finding common ground in Ratatouille.

I read that you had three auditions for this. Did you feel good after each one?

The first audition I had, there was no script available to read at the time. There were just two audition scenes. And I remember thinking as soon as I read just those two scenes, without having context for the rest of the story, that I felt like I knew this man, or at least knew an interpretation that I’d like to give. That’s quite a rare feeling. Oftentimes, it’s about you bringing yourself to a character. But I felt that Schofield and I — that I knew him quite well already.

I met Sam [Mendes] on the second audition. He explained this idea of how the film will be shot, and that was just so exciting and inspiring. The third one Dean [Charles Chapman] and I read together, and then it went from there.

Was that your first time meeting Dean?

Yes. Yes it was.

That friendship, between Blake and Schofield, is sort of critical to making this movie work.

Yeah. First of all, that’s the context for the story, and, of course, that’s essential. But it’s a context that provides a circumstance. It’s used to explore the human experience. I think Sam’s talked about this: The film’s really about what it is to be alive. I think we get a sense of what that is most when we’re stretched, when we’re almost taken physically and emotionally to our absolute limits and where we’re in extremes. It kind of roots us with what is most important. And I think that’s what this journey is all about.

Can you tell me more about your first meeting with Sam? What did you talk about?

I remember the first thing that he asked me, which is a question that I don’t think I’ve ever been asked before in an audition. He said, “What’s been your most exciting directorial experience, and what has been the most pleasurable experience of work that you’ve ever had?” And he says, “There’s no right or wrong answer. I’m just interested to know. And it might be different than how I work, but I’d just like to know.”

I’ve never been asked that question before. I thought it was a lovely, open, quite probing question. Work means so much to me, and I think to everyone involved, that it blurs a little bit with your real life. You understand things about yourself [through playing someone else]. Sometimes they’re close to you, sometimes they’re far from you, but there’s always a core that is shared. I think that was a really insightful way of getting to know me as a person — was to ask about work.

I’ll ask you the same question, then: How do you like to be directed?

I think I like to be pushed. I like when someone suggests a direction to you and they give you a very clear note, but a note that can be specified in many different ways. It reminds me of a job I did years ago, which was a small Scottish film called For Those in Peril. There was a lot of improvisation involved with that one. There’s this beautiful relationship within the film between the character that I play and the girlfriend of my older brother, and we’re both sort of reeling in the grief of having lost my brother. But then, there’s this scene where my character becomes sort of too intense. This friendship means too much for him, and psychologically he’s spinning out of control. I remember Paul, the director, just said, “You know, you can do anything within a safe space.” He said, “But scare her,” in that way that I knew exactly what he meant by that. I knew exactly what my goal was, but it was completely up to me the way in which I expressed that or kind of did that. That sort of very clear but very open direction is what I like best.

That’s an interesting contrast to 1917, which is so tightly scripted and choreographed. After a screening, Sam said there were six months of rehearsals?

We were blessed with that amount of time because, with this film, there’s so much crafting of the pace and the rhythm, which is essential to the story. Something I learned a lot from Sam is he talked often about the rhythm of storytelling and the rhythm of our story, and how that affects the viewer and the audience. Obviously, we can’t craft that in the editing, so we had to spend a lot of time crafting the rhythm of the story beforehand. With the camera never cutting, the gaps that are left in between the lines affects the length of the set.

Say that you’re with Dean and I having a back-and-forth and then there’s a pause because we’re registering what the other one said, but we’re jogging to get somewhere. It might take up 50 meters of trench. We needed to sort all of that out because we needed to commit to a rhythm that felt truthful and that felt exciting. So that’s what we were doing mainly for the six months. We were going to locations — which were, at that stage, completely empty fields — and pacing these scenes out. Dean and I would work out how we wanted to act them, and Roger and the camera team would work out how they wanted to shoot them. The sound team would be working out how to record the sound. Then, we would lay stakes out in the ground as markers as to where things needed to be.

What did you enjoy about that process, about spending so much time with the material?

The best thing about that was that I got to learn a really three-dimensional understanding of a filmmaking process. I think oftentimes as an actor, you’re to yourself. Sometimes it’s vital — you might be keeping yourself to yourself — or it’s because of, to be honest, a social structure that’s there, which isn’t always necessary or healthy. You’re kept separate and you’re looked after so well that you aren’t party to a lot of the conversations [among the crew]. You turn up at the last minute, you do your thing, and then you go and it’s done. But it stops you having an awareness of how all things work together. But with this film, everything had to be worked in harmony and in consideration of each other.

But during this process, you were also working out to get in shape?

I mean, there’s so much that we did. Every morning, Dean and I would be doing military training. We would be in the costumes. With the makeup. We were able to test haircuts and see, What haircut would they have before the war? How would they have wanted to have their hair cut when they got there and then how long have they been there since they’ve had their hair cut? We could work out how the costume needed to be, all the details.

Who these characters are is kind of what is underneath the film. For me, Schofield is someone who is on the edge of breaking. I think if he feels like if he talks about home, if he lets his head and heart go there, he can never function where he is right now. So he sort of learned to close himself down and hold himself together. It was very important to me to know what his home was, to know who his family were. All of that research was just something that I did privately. That came from a mixture of imagination and just looking at all the references. The war poetry was an amazing way into it, first-person accounts, literature — art, as well. The war painters were a real insight into it.

Once we got to understand that there was a relationship between the way we moved as characters and what the camera itself sees, the theme of bearing witness to a moment became a theme … Sorry — I know I’ve just rambled at you.

No, it’s okay.

But it’s because all of that was just done gradually — day by day by day by day — for six months. Then we got to shooting and then it was its own beast again.

What did you shoot on the first day?

We didn’t actually shoot anything on the first day, because the weather wasn’t right. All we did was rehearse. So it was quite funny: Everyone was gearing up to the first day and then we got there and the sun was out, so we couldn’t shoot. So we just actually rehearsed three days’ work all day. It’s funny: By the end of the first day, we were behind schedule. But by the end of the second day, we were ahead of schedule because we’d caught up with everything.

Something that struck me about the movie, that maybe you also just mentioned, was this restrained quality to Schofield. There’s not a ton of dialogue in the script, but so much is happening in your face, behind your eyes. I’m wondering where you think that quality comes from, or if you recognize it in yourself.

I don’t know. I don’t know if it’s for me to say. When I first read the scenes, I felt like I knew Schofield’s way of being. The job that I did just before 1917, which is actually coming out afterward, was a film called the True History of the Kelly Gang. It was by no means going to war, but physically and emotionally, that’s the most immersive and testing experience I’ve ever had at a job. I remember in the last two weeks of that, we were doing this particular sequence which was really violent and very emotional and kind of violent in its emotions, as well.

Acting is an incredible experience, but I remember getting to work and I’m thinking, I’ve got enough energy to do the work, but if I acknowledge how I’m feeling, I’m going to break down. And I think if I break down, I’m not going to be able to get back and be able to see to the work. So I’m just not going to say anything. I’m just going to get through it because I know that we’ll finish it soon. So taking things day by day because of the fear that if I do break, I’m not going to be able to go back to it.

That if you take a moment to sit with what you’re doing, to register it, then you won’t be able to do it?

You know what I mean? That was something that I felt in Schofield. You see chinks of it when Blake starts completely innocently asking again and again about his family. “Why do you do that? Why don’t you take on her home? Why do you do this? Why don’t you talk about them? If you love them, why, why, why, why, why, why, why?” I think I recognized it [in Schofield] because I’d only been home for about a month from the Kelly Gang job when I auditioned for Sam, and I saw it [in myself]. That feeling was just very fresh. That feeling of, like, “I can do this, but I can only do this if I keep myself here. If I let my heart and head go anywhere else, I’m not going to be able to function here. And I know that I can’t leave here, so I just can’t go home in my heart and my head yet.” And that is something that I kind of just recognized and at the time was very present in my understanding.

What was it like working with Roger?

Oh man, it’s amazing. It’s an honor. His reputation precedes him. He’s a legend and a master of what he does, so you’re sort of ready to meet a huge personality. But he’s a very quiet man, and he just loves his work. He’s just really curious and inspired by storytelling and his way of storytelling, which is with light and with camera and vision.

Is there a sense, when Roger Deakins is shooting you, that this is the best you’ll ever look? Because he’s just so good at what he does?

No, no. I think you know from Roger that the stories are always most important, rather than how you look. Him and Sam, they’re both fluid and flexible in how they work, but there is a kind of an uncompromising nature with the work. I don’t know if anything can ever be perfect, but because we knew that we couldn’t edit these scenes, we are always gunning for as close to perfect as can be.

On the very first day, having the conviction to go, “Yeah, I’m sure the studio is keen to get us going, and they’ve given us six months of rehearsal, but if we start today, the aesthetic of the film will not be the exact aesthetic that we planned for and that we think is best for the story. So we’re not going to start today. We’re just going to rehearse, hope that tomorrow [is the day]. And if it’s not right tomorrow, we’ll rehearse it again and we’ll wait till the next day.” That commitment and conviction to what is right for the story is something that’s amazing with Roger.

This is my last question: Tell me everything about those rats.

Those rats?

The big ones, running around the German trenches. Were they real, or were they CGI?

I don’t want to ruin the magic! I think there’s a mixture of some of Britain’s finest rat actors, yeah. I think one of them was in Ratatouille and he’s had a quiet time of work over the last few years. But you know, I mean there’s some things which have a little bit of help with special-effects magic. It was a mixture of stuff.