Terminator: Dark Fate was a difficult shoot for Mackenzie Davis, who plays Grace, a new super-soldier who's part-human, part-robot. The actress had to tone herself up by hitting the gym, all to present herself as the enhanced assassin we see in the final movie. Sitting down with GamesRadar+, Davis discussed the shoot and the pressures of taking on such a huge franchise. She also teased her upcoming movie Irresistible, directed by John Stewart and co-starring Steve Carell. Read the Q&A below, edited for length and clarity.

Earlier this year, our sister publication Total Film was on set, and saw this huge set-piece on a plane that was built on a gimbal, turning around like a washing machine. What was that like?

It was amazing to finally see the set because we heard tell of it all shoot, that it was being built in this distant warehouse somewhere. The day that we finally got to go into it, they were doing a test and we were just sitting down. It's funny how limited our perspective is sometimes, because you just change the way the floor and the ceiling looks and you're like, "Am I upside down?" So, we're always in the same position.

That's the coolest thing about these movies, these huge blockbuster movies. They attract the geniuses, the absolute best in every single field, to execute their works: the best engineers, the best visual designers, the best companies that will do CGI. And so you get this exposure to the most amazing intellects over the course of making a movie like this it's really so cool.

It must have been really draining, physically, going through all this gnarly stuff.

It was the hardest thing I've ever done. It's funny talking about it now, because I would say I'm not an athlete, and I'm not terribly motivated to do athletic things. The lack of sleep, and the amount of work that went into this movie... I feel very proud, and also shocked, that I did it.

Are you still on the same fitness regime now?

No. But I do say I think that the great gift that Terminator gave me was the ability to walk into a gym and feel completely at home. I don't need anybody to train me. I feel totally comfortable, which is such a skill set. I never felt comfortable in a gym or knew what to do, and especially it feels like a very male space. Having the ability to enter that space and know all the ways I want to use my body, it's such a cool side benefit of this.

It's interesting you talk about feeling comfortable in a gym. Your first scene in this movie sees your character fight without any clothes on. How was that on set?

That scene, my entrance scene where I'm naked, was supposed to be shot in the first month of the movie. Before you shoot a scene like that, you do a bodybuilder slim down so all of your muscles pop. For about 10 days before, I was on this really difficult stretch, and I sunk suddenly into deep depressions because the regime was so limiting. You basically can't interact with anybody. You can't be social on your days off because, unless you just want to drink water with a pal.

And then, they moved the date of the arrival scene and it was a month later. And then I did the slim-down again, and then then they were like, "No, we're going to shoot it in a month." They did that four or five times, and by the time we actually shot it, I was so ecstatic, just hysterically happy that I was going to get to eat after the scene and then it was in another tease! I was so confident and could not care less about being naked. My trailer was filled with baked goods, Swedish candy from my trainer, I was getting pizza on the way home. So, maybe under other circumstances it would have been awkward, but I was cloud nine.

One of the great things about this film is that you have these three leading women – yourself, Linda Hamilton, and Natalia Reyes – which must have been quite empowering?

Linda's incredible. But I think less the sort of socio-political effect of being empowered. We were just actors who liked the roles. I really believe in representation, and I think there's so many important aspects to having a movie led by three women that look so different. We're different ages and from different countries, and there's Latina representation. But that only matters in this stage. When we went to work, we were just excited by these great roles to play. That's the progressive thing: having good roles for women and no longer watching other people do the good work, or be the bad guy, or have the feelings.

With Terminator, you've taken on a huge franchise, and the new movie forgoes the other sequels. Did you feel pressure to impress when taking the role?

I felt really nervous about taking the role. I was initially not nervous, and then when I got the role I had a bit of a meltdown. I was like, "I can't do this, I am not this person, I don't know why they cast me, I'm not good at any of this stuff." And there's a lot of sort of masturbatory talk about stepping outside your comfort zone, but not being in your comfort zone is deeply uncomfortable. It's not just thrilling! I say this as a joke, but it is a real story, because every day I was like, "I don't know why you cast me! I don't know what I'm doing here!" I remember, on day 96, I finished and Tim was like, "That was good," and I was like, "I don't know, I don't think I'm ready for this role!" It was this long uncomfortable process of finding this thing. Sometimes it felt good and sometimes it felt bad. I'm sure a lot of that was because of the enormity of the thing and how it's received is a huge thing. But also, you're playing on this operatic level, and you can't act the way you act in your tiny little chamber dramas. You have to be bigger and you have to commit to this larger scale thing and I found that really intimidating, to take on the enormity of the stakes in this world.

You've been in Black Mirror and Blade Runner 2048. Did you see yourself, when you started, being in predominantly science-fiction films and shows?

It's something I enjoyed, but if I would have designed my career, it's not what I imagined for myself. Looking back it all makes sense though. There's often more interesting roles in science-fiction; a more abundant variety of interesting roles for women than there is more contemporary movies. Without trying, the things that really moved me and excited me that were big ideas and, they just happened to be in science fiction. It's funny, I'm in another upcoming project that's sci-fi, and I just love this character. You just keep want to do the stuff that the moves you and, sometimes, those are extreme ideas or people finding themselves in extreme situations and learning how to to adapt to those. But, it's probably good for me to stop doing it...

One of your next film is directed by Jon Stewart. Can you tell me a little bit about it?

Okay, I love this movie, I think it's so great. The script is one of the best scripts I've ever read. Jon Stewart is an American hero and does not disappoint in real life. He's such a generous loving human being, and the movies is this really funny, incisive look at a small town mayoral election campaign that obviously stands in for larger political themes better. He's just such an incisive, funny, accurate person, so his movie reflects all of that.

It's interesting that your next project is so political. Terminator: Dark Fate also makes some political statements, featuring a wall between Mexico and the United States. Is that important to you, to be involved with projects that make statements?

Yeah, I think everything's political. If you are making a movie in our current era, you're either ignoring or addressing the state of the world, explicitly or implicitly, so I want the things that I participate in to have something to say. I do not want to be in something that's ignoring what's going on in the world. It doesn't need to take a stand, but addresses the world right now and says, "Here's what the world looks like fictionalised. What does it feel like to live with that? Do you care as much in real life?" That's how it feels with a lot of sci-fi, that it's so close to our current reality but we like seeing these five degrees of separation, the more heightened disaster version and that lets us off the hook. But look at climate change. We're entering uncharted horrors on our planet, and yet we can't stop talking about the rise of the machines. There are more interesting horrors to await us, but we love the fantasy of disaster and not the reality. Obviously.

Terminator: Dark Fate is currently playing in UK cinemas and reaches US theatres November 1. Before you see the film, you may want to prepare yourself by reading our extensive Terminator timeline explained.