Mark Rylance made sure his new movie Dunkirk didn't "glamorise" war before singing onto it.

The Oscar-winning actor stars in Christopher Nolan's latest blockbuster, based on the rescue of Allied soldiers in France during World War II.

As a patron of charity Peace Direct, dedicated to bringing an end to war "one person at a time", Rylance was extra wary of how the famous events from 1940 would be dictated on the silver screen.

"I had a conversation with Chris, right at the beginning," he recalled to Saga magazine. "It didn't feel like it was glamorising war, but I just needed to check that that was his opinion, too - and it was. I speak out about conscientious objection and all that, because war exists.

"It was important to me to be part of a film that portrays the situation faithfully and truthfully, where people are really dying and there are real consequences. It's not a game."

The craft that we were in was from the 1930s; the soldiers were on very old warships that they resurrected for the film," the 57-year-old actor explained. "And they were like tin cans. You think, 'My God, the bravery of it!' The machinery of warfare at that time had great guns and engines, but the shielding and protection was pretty lousy."