Liam Neeson was "terrified" when he started shooting his new movie.

The actor portrays Ottway in The Grey, which follows a team of oil drillers who have to survive when they are stranded in freezing temperatures.

Director Joe Carnahan was adamant everything had to be as realistic as possible, while Liam realised as soon as filming began.

"It was terrifying. I'll be really honest. The first week was very, very scary. We were in minus 40 degrees I remember thinking, 'We're never going to finish this film. It's just going to be physically impossible because all you think about is trying to stay warm,'" he admitted.

Liam was gripped as soon as he read The Grey's script. He couldn't understand how much of the movie would be shot, but decided to trust Joe's vision completely.

"It was the script and I thought, 'It's going to be impossible to shoot this,' but I was intrigued because it was Joe and I love Joe. I don't know what I thought," he recalled to ET Online.

"Because of the way the scenes were described, the extremes of temperature blizzards, wolves, fighting wolves, being attacked by wolves, I thought, How is he going to do this?' and he said he didn't want to use CGI. And indeed there is little CGI in the movie all the weather is real."