Nicholas Galitzine says bulking up for Masters of the Universe was the toughest challenge of his career

Nicholas Galitzine declares bulking up to become He-Man in Masters of the Universe was "the hardest thing [he's] ever done".

In the upcoming reboot, the 31-year-old actor replaces 68-year-old Dolph Lundgren - who played the superhero in the 1987 live-action version of the fantasy-romance movie.

Despite finding getting into an even stronger shape tough, Galitzine described it as a "really interesting experience".

He explained to People: "It's the hardest thing I've ever done; it was a daily challenge. But there is something incredibly empowering about committing to something so heavily.

"I've never had a challenge like that before, which really every single day you have to wake up and you can see the peak of the mountain vaguely, but especially when you're bulking. I think it would be insincere for me to say that it was easy."

Galitzine even admitted he felt "body dysmorphia" amid the transformation.

The star - who left a "definite dent" on the side of the bed he sleeps on because of how large and ripped he became - added: "You don't recognise yourself, you don't fit in any of your clothes anymore."

However, Galitzine - who is not keen on maintaining the sculptured physique "all year round" - is grateful to be playing the superhero in Masters of the Universe.

Galitzine said: "But really, I'm so gratified that I got to experience it and trying to fit this very larger-than-life character."

Back in June, the actor took to Instagram and gave a first look at his He-Man look.

In the shot, Galitzine looked strong with his back to the camera as he flexed his arm muscles in his costume, which consists of arm gear, tall combat boots and a longsword.

And in the post's caption, Galitzine shared the "incredible" experience he had playing Adam, Prince of Eternia, and He-Man in Masters of the Universe.

He penned: "Well, that’s a wrap on Masters of the Universe. It has been an honour shouldering the responsibility of playing Adam and He-Man," he wrote. "It’s been the role of a lifetime, and I put everything into it."

Masters of the Universe - which is set to be released on June 5, 2026 - sees He-Man battle it out against the evil Skeletor (Jared Leto) to save planet Eternia and to protect the secrets of Castle Grayskull.

The movie also stars Sam C. Wilson (Trap Jaw), Kojo Attah (Tri-Klops), and Hafthor Bjornsson (Goat Man).

Camila Mendes appears in Masters of the Universe as Teela - Adam's love interest.