Charlize Theron has endured a lot of onscreen action in her life: a bravura 10-minute, one-take brawl in Atomic Blonde, an epic 18-wheeler desert chase in Mad Max: Fury Road, and immortal duels in The Old Guard.

But her latest film, Apex, introduced her to a group of brand-new challenges: rock climbing, kayaking, taking a running leap off a cliff, and even scaling a billboard in real time in the heart of New York City’s Times Square.

Theron soldiered through, performing many of her own stunts and working with the help of director Baltasar Kormákur and a killer stunt team. She loved the experience so much, in fact, that she has called Apex her “favorite movie she’s ever made.” She does have one lingering hard feeling, though. “I can’t look at a kayak,” she recently told Krista Smith on a new episode of the Skip Intro podcast. “It’s that bad.”

Apex follows Theron as Sasha, a grieving rock climber who finds herself trapped in a deadly cat-and-mouse game in the Australian Outback, with a psychopathic serial killer (Taron Egerton) close on her trail. The film launched at No. 1 on Netflix with 38.2 million views after it debuted on Netflix on April 24.

Theron has nothing but glowing things to say about her co-star. “I’ve been a fan,” she told Smith. “And so I was very excited about the chance that he would say yes to do this.”

When Theron and Kormákur sat down with Egerton to offer him the role, they got off to a running start, much like their characters. “From the moment that we met Taron, he was tapped into something that was phenomenal,” Theron told Smith. “It’s very, very impressive when you work with an actor that just has a gut reaction to pages that are coming in, to ideas — and he always made things better.” 

For Theron, Apex marks a career high, but it was also a learning opportunity. “I hope I work with other directors that push me as hard as [Kormákur] did, but he also gave me an incredible amount of kindness,” she said. 

Working with Kormákur and the crew of Apex reminded Theron of an experience during one of her early performances, opposite Michael Caine in the 1999 film The Cider House Rules. As she tells it, Theron approached the storied actor and stumbled through asking him which of his films he was most proud of. 

“He said, ‘I wouldn’t be able to tell you which one of my movies [was] a success at the box office, but I could tell you very vivid memories that I have with each and every single person, and that’s the stuff that stays with you,’ ” Theron recalled. “You walk away feeling so enriched because you get to be around brilliant people who are some of the best in their industry doing their job, and then you get to know them on top of that too.”

For more from Theron, including memories from her Oscar-winning performance in Monster, learning to climb for Apex, and her Real Housewives fandom, you can listen to her full episode of Skip Intro with Krista Smith.

Apex is now streaming on Netflix.