Actors Tom Hiddleston and Genden Phuntsok didn’t climb the real Mount Everest while filming Tenzing, but they did climb very real, very dangerous mountains in the Himalayas and New Zealand.

“We did this for real,” Hiddleston told Decider in a recent junket interview. “No sound stage, no studio, no green screen.”

Tenzing, a new biographical drama that began streaming on Apple TV today, stars Phuntsok as Tenzing Norgay, a Sherpa mountaineer who, alongside New Zealander Edmund Hillary (Hiddleston), became the first people to summit Mount Everest in 1953. The expedition, led by British Army officer John Hunt (played by Willem Dafoe) is often told as a story of British victory. But director Jennifer Peedom and write Luke Davies re-center the story to its rightful protagonist: the man who was raised in the shadow of Earth’s tallest mountain, and dedicated his life to both climbing it himself, and to helping foreigners (usually white Europeans) climb it.

Phuntsok, a Tibetan actor making his English-language film debut, learned two new languages for the role: English, and Sherpa, the language of the people indigenous to the mountainous regions of Nepal, India, and Tibet. He spoke with the real Tenzing’s eldest son, Norbu Tenzing, who is an executive producer on the film. He spent 10 days living with with renowned Sherpa sirdar (head climbing guide) Phurba Tashi Sherpa, learning about the Sherpa traditions and responsibilities of accompanying climbers up the mountain. And he spent months training for the physical demands of the role.

“I really hope one day I can try to climb Mount Everest,” Phuntsok told Decider, before quickly adding with a laugh, “I don’t believe that I can do that! I would like to try.”

Hiddleston and Phuntsok spoke to Decider about the physical challenges of the film and their respect for the mountaineers who attempt the climb.

DECIDER: Can you talk about the physical challenge of the film, of the training and filming in the real mountains in New Zealand and Nepal? It looked very cold and very scary from my point of view.

Tom Hiddleston: Well, yes! It was challenging and thrilling, and important to say we did this for real. No sound stage, no studio, no green screen. We were on real mountains, in the foothills of the Himalayas in Nepal, and also on the high mountains of the South Island of New Zealand. So when you see Genden climbing out of a crevasse as Tenzing, that’s Genden at the bottom of the crevasse, and climbing up the wall of ice. When you see me as Edmund Hillary falling into a crevasse, that really happened to Hillary, and it really happened me. They dropped me into a crevasse, and I had to climb out of it. There’s a 40-foot ridge of rock and ice on Everest, called the ‘Hillary Step’ now, because Hillary was the first to summit it. We found a 40-foot ridge of rock and ice outside Queenstown, in New Zealand and we climbed it for real. When you look over the edge there’s a precipitous drop all the way down to the bottom. Don’t look down and don’t fall down! 

Genden Phuntsok: Yeah!

TH: But it was our honor, our privilege, our thrill, because as actors, you know we’re not performing, we’re doing. We are living in the shoes of these great men and following in their footsteps, literally, in the same environment. So it was a challenge but we embraced the challenge.  

GP: I want to tell the point, the day we filmed the big crevasse—we filmed that two days. I’m on the edge of the crevasse and I pull up Tom. All day we filmed, I’m just climbing in the snow—really climbing. Your [points to Hiddleston] weight is hanging, pulled back from my body, and I climb in front. We shot that many times. In the end, like the afternoon, when we’re wrapped, all my body was wet [with sweat]. I can feel that the outside is really cold, but inside is really hot, because I worked so hard.

TH: Yes, you’ve been working. So intense!

GP: When I got to the set, when I took off my jacket, I saw the fog coming up here.  

TH: Yeah, it’s real work!

Is climbing a dangerous mountain like Everest something either of you would want to do for real? Do you understand why people like Tenzing and Hillary feel a calling to do these seemingly impossible tasks?

TH: Climbing a mountain like Everest, or climbing any high mountain, is an act of worship. It makes you feel so alive. It is, of course, incredibly dangerous and perilous. It’s the focus, the attention, that you need—you’re aware you are very small, in the face of truly awe-inspiring, majestic beauty. Yet every step you make, you have to test the probity of the snow that you’re on. You have to make sure you’re not going to fall down a crevasse. Every knot you tie in a rope, every calculation you make about how much oxygen you have left, how much daylight remains… it makes you feel intensely alive.

That is the passion and the love that Tenzing and Hillary have for these mountains. They felt free in the mountains, even as they have to be careful. Because it takes such competence, it takes such awareness. Genden was talking about the weather—you underestimate the knowledge and the experience of these men in looking down the valley, seeing the cloud formations. They can read the wind coming in from two hours distance and thin, “We have to down the mountain, and we have to be back at camp in the next hour, because weather’s coming in. ” They revered mountains for the sake of the mountains. It wasn’t about their ego.

Would I do it? I’d love to. I’m a father of two young children I love very much. I think some of the risks of Everest itself are too great. It would be irresponsible. I hold in my heart the privilege of this experience. I got to live in the shoes of Edmund Hillary, who is one of the greatest mountaineers of all time. And maybe that’s where my Everest expeditions end. But I’m already more fortunate than many others.

GH: I’m from mountain. I really love mountain and nature, especially just walking in the valley near the river. The sounds of the tree, and the birds, or the wind. […] I think all the mountaineers that climb, or they’re just hiking, it’s not just for some big purpose, or target. They want to really enjoy nature [as they] climb higher, on the way… […] You just enjoy the nature, the sounds, the wind on that approach to the mountain. Even [the] summit, it’s just enjoy the nature. I think that’s what they really want. For, me it is. And I really hope one day I can try to climb Mount Everest. I don’t believe that I can do that! [Laughs.] But anyway, I would like to try to, even just to go to the base camp or higher. If I can, I will try that. I [would] really love that.

Tom, as a British actor playing a New Zealand character in this film, what’s your take on the portrayal of the British attitude toward contouring nature and their relationship with the Sherpa people?

TH: I have to give credit to Jennifer Peedom, our director, and Luke Davies, who wrote the beautiful screenplay, who were able to reframe this very familiar story from a new perspective—the perspective of Tenzing. Tenzing, at the center of his own story, in a way which does not disrespect the achievements of the British climbers. It just re-positions their point of view.

1953 was the year of Queen Elizabeth’s coronation. John Hunt, played by Willem Dafoe, I think felt enormous pressure for the expedition to be successful. There was still a sense of romantic exploration from from the European nations about going to the wildest spaces. Hunt was a military man, and there was a sense of military planning in terms of trying to get to the summit. Tenzing’s attitude is much more spiritual. He sees Everest not as a mountain to be conquered, but a goddess to be revered—a mother into whose lap he might climb. The suggestion is that Tenzing’s presence and leadership on the expedition helped to shift the attitude of the British climbers. Perhaps their own response to the mountain might be more spiritual.

What’s beautiful about the film is it really honors Tenzing’s place in the expedition, and Hillary’s, and also that of John Hunt—that he was able to see that Tenzing and Hillary were cut from different cloth, that they had extraordinary skill and competence as mountaineers. Hunt stood behind Hillary at the end of all of it, when Hillary said, “We didn’t conquer the mountain. The mountain accepted us.” So, the achievement really is shared. It’s a testament to all these different people approaching the experience from different points of view. I think it shows that we’re all so much greater than our differences. We’re united by the things we share more than we’re separated by the thing which divide us.

This interview has been edited for clarity.