Liddell, who famously refused to run on Sundays due to his religious conviction, was working as a missionary in China when he was captured by the Japanese. He died in the camp in 1945.

Shakespeare in Love star Fiennes tells WENN, "He's a great character and sadly never got out of the concentration camp. When the Japanese invaded he got caught up.

"Even when (British Prime Minister) Winston Churchill secured him a ticket out, he gave his ticket to a pregnant lady and she got out. This is about his trials in the concentration camp and how it tested his faith. I spoke to a gentleman in his 90s who shared a room with him in the concentration camp who said what the world doesn't know is he broke his beliefs of not working or playing games on the Sabbath.

"He went against his beliefs which he's really famous for in (the film) Chariots of Fire, but under duress and really bad conditions it's interesting how one has to adopt a different attitude to your faith if it means getting other people through a difficult time and making them happy in that moment. I thought that was interesting."

The gold medallist was portrayed by fellow Scot Ian Charleson in 1981 movie Chariots of Fire.

Fiennes, who has also been cast to play Michael Jackson in a new British TV comedy, admits it was fascinating to shoot The Last Race in China, where Liddell was born, adding, "What's interesting is a Chinese director made the movie and it's a Christian movie in a land where Christianity doesn't exist; the party line is it's an atheist country, so that is revolutionary."