The actor told PA that shooting the movie in Scotland put the performers in the middle of some harsh weather.
"l'll think twice about making a film in Scotland again, especially in November," he explained.
"But part of having Kevin Macdonald at the front of this as the director, he's a documentarian at heart, I think, as much as he is a great feature filmmaker, so he really wanted to put us at the frontier."
He added: "It's about people crossing boundaries and going into unknown worlds, and to achieve that we had to go up to the most remote parts of Scotland we could find. The physical landscape of the film is very much a character in the movie."
The Eagle is currently playing in US cinemas, and is released in the UK on March 25.