Henry Cavill was "stressed" about getting into shape for 'Immortals'.

The British actor portrays muscular Greek warrior Theseus in the Tarsem Singh-directed epic, and although he found filming the movie "very exciting", he did get nervous the closer it came to shooting because he was worried his physique was not good enough.

He said: "It's very exciting. More exciting than it is terrifying, really. I felt the pressure at one point. I had to be in a certain kind of shape, it was getting close to punch day, and I only had so long left to recondition the body.

"I suppose that I was a bit stressed over that. That's been the most difficult thing, just maintaining that throughout. But otherwise, extraordinarily exciting, especially working with a director like Tarsem, who has boundless energy."

The star, who recently signed up to be the next Superman, admits he was glad to have a stunt double during taxing fight scenes so he could take some time out to rest.

Henry told Comingsoon.net: "You're throwing all the emotion and the aggression into it, couple together, it's truly exhausting.

"Thankfully my stunt double Alain Moussi, who is fantastic, did a lot of the shots from behind, so I could save my energy for an hour or so and then go back in and do the reverse."