How Katherine Waterston Got In Shape To Kick Some Serious Butt In Alien: Covenant

In the latest installment of the Alien franchise, set 10 years after 2012’s Prometheus, a new heroine has been charged with kicking some major alien butt: Katherine Waterston plays Daniels, a chief teraformist on a colonizing mission to a new planet. And after an advanced screening of Alien: Covenant, which hits theaters Friday, I can assure you that Waterston embodies the strong female lead that’s been a staple of the Alien movies since Sigourney Weaver’s portrayal of Ellen Ripley, the original badass known for beating down extraterrestrials.

As you might imagine, sparring with (or running from!) blood thirsty—and let’s face it, pretty freaking scary—creatures isn’t an easy task. Translation: Waterston needed to be in great shape.

“I was so nervous that [director] Ridley [Scott] wasn’t going to let me do the stunts,” she said during a pre-screening talkback with cast members. “There was a sort of fit test at the beginning that nearly killed me, but I didn’t want to seem like I couldn’t handle it, because I thought they might take the fun moves away from me.”

But the 37-year-old actress explained that she didn’t arrive on set in the best shape of her life on purpose: “I didn’t want to seem like some kind of warrior at the beginning of the film, because I feel like that journey happens within it, so I didn’t want to come in too ripped,” she said.

Waterston’s plan worked: She got progressively fitter just by playing her role, she said. “A lot of the training happened on set because we were carrying heavy packs and carrying really heavy guns—for me it was heavy.”

Still, Waterston knew she needed to build muscle before filming began to avoid getting hurt on the job. “I didn’t want to rip my shoulder out my socket or something,” she said.

RELATED: 11 Best Exercises to Get Strong, Toned Arms

One of her strengtheners of choice: “curls, really heavy bicep curls.” Which totally makes since considering you’ll see her wielding gigantic guns, and swinging and climbing around a space shuttle for two-plus hours.

Channel your inner warrior and try a few: Stand tall with feet hip-width distance apart and arms at sides, a dumbbell in each hand; palms face forward. Without moving upper arms, bend elbows and curl weight toward shoulders. Slowly lower back to start, and then repeat.

Prefer to do curls with a cable machine? Check out the video below to see the proper form.

Clearly Waterston nailed her training approach for the sci-fi horror flick because actor Michael Fassbender (who plays the androids David and Walter in the film) had this to say about his costar: “She was fearless.”