Alexander Skarsgård had wanted to play a Viking for years. When Robert Eggers finally cast him as Prince Amleth in ‘The Northman’, he knew the role would demand far more than growing a beard and swinging an axe. He had to look, move, and fight like a warrior who had spent his entire life surviving in one of history’s harshest worlds.
The preparation pushed him to his limits. Skarsgård trained relentlessly to build a larger, more powerful physique than the one audiences saw in ‘The Legend of Tarzan’. Then came months of filming in freezing landscapes, deep mud, and punishing weather. The experience eventually left him dealing with whiplash and lingering back problems. Looking back, he called ‘The Northman’ “physically and mentally the most difficult job I’ve ever had.”
Building Amleth Was Nothing Like Building ‘Tarzan’
Skarsgård began training while he was still filming another project in Vancouver, but the work intensified after production moved to Belfast in early 2020. Most mornings started inside a garage gym before he headed to the studio for stunt rehearsals that lasted the rest of the day.
Related: Why Robert Eggers’ ‘Werwulf’ Rewrites Everything You Know About Werewolves
Trainer Magnus Lygdbäck already knew what kind of warrior they wanted to build. “We knew that we wanted something a little bit bigger and thicker than Tarzan,” he explained. Unlike his previous transformation, getting lean wasn’t the priority. “We weren’t too concerned with the body fat.”
That decision completely changed the training plan. Instead of burning calories through endless cardio, Skarsgård focused on adding muscle and functional strength. The goal wasn’t simply to create a bigger body. Amleth needed to fight, sprint, climb, and swing heavy weapons without looking like he had spent months inside a gym.
Lygdbäck designed a demanding four-day split that Skarsgård repeated five days a week. Legs came first, followed by chest, back, and arms. Core work happened every day, while shoulder and hip mobility exercises prepared him for long stunt rehearsals. Amleth belonged to the Berserkers, whose warriors drew strength from wolves and bears. “We wanted that size and strength,” Lygdbäck said, “but we also wanted him to be able to move like a wolf.”
The Shoot Was Just As Brutal As The Training
Even after months of preparation, filming proved even tougher. Skarsgård jumped straight from playing tech billionaire Lukas Matsson in ‘Succession’ to crawling through Icelandic mud as a Viking prince.
In Case You Missed It: 10 Actors Who Went To Extreme Lengths For A Role
“The days were really long and hard, and we were out in the mud, and up on these mountaintops with the wind and the cold,” he recalled. The contrast could not have been more dramatic. “The week prior, I was working on the television show ‘Succession,’ on which I play a tech billionaire in a villa on Lake Como.”
He laughed about how quickly his surroundings changed. “I literally went from playing one of the richest dudes on the planet in a crazy, beautiful villa surrounded by yachts and helicopters and luxury, and got on a plane and flew to Iceland to get shackled and dragged through the mud.” The experience became “a waking-up moment and a humbling experience.”
His co-star Anya Taylor-Joy endured the same conditions. “There was one day when the mud was up to my knees, and it had frozen overnight, and I’m barefoot,” she remembered. Even Taylor-Joy, someone who rarely complained on set, eventually reached her limit. “It had got to a point where I just squeaked out, ‘Please!’… If Anya’s saying, ‘Can we please roll? I can’t stand here any longer…'”
Authenticity Came At A Physical Cost
Robert Eggers insisted on making the Viking world feel as authentic as possible. Rather than asking actors to imagine freezing temperatures or harsh landscapes, he placed them directly inside those conditions.
Taylor-Joy believed that approach changed every performance. “Because of the authenticity that we’re bringing to it, in terms of the costume, in terms of the landscape… we don’t have to imagine much. You can just inhabit. You can just exist.” Living in those conditions also gave the cast a new appreciation for Viking life. “It gives you a real appreciation as to how tough these people were. Because nothing about this life is easy.”
Skarsgård paid a physical price for that realism. The demanding action scenes and constant punishment left him with whiplash and back problems that lingered after production wrapped. Every fight, sprint, and tackle came on uneven ground, often in freezing temperatures while wearing heavy costumes and carrying weapons.
The finished film shows exactly why Eggers refused to make things easy. Amleth never looks like an actor pretending to be a Viking. He looks exhausted, battered, and dangerous. That realism came from months of brutal preparation, relentless filming, and a production that demanded everything from its cast. For Skarsgård, ‘The Northman’ wasn’t simply another physically demanding role. It became the toughest job of his career, and one his body still remembers.
You Might Also Like To Read: “I Felt Like a Jerk”: Matt Damon Shares the Humbling Lesson Christopher Nolan’s ‘The Odyssey’ Taught Him on Day One
