Christopher Nolan was inspired to make 'Dunkirk' 20 years ago

Christopher Nolan has revealed he along with his producer wife Emma Thomas were first struck by the idea of making "Dunkirk" over 20 years ago when the couple was out on a boat trip.

The 47-year-old filmmaker, who has collaborated with Thomas on high-level projects including "The Dark Knight", said their voyage turned out to be quite turbulent which made them reflect on the difficulties the soldiers faced during World War II, reported PageSix.

"I remember Emma and I made a trip with a friend of ours on a boat - many years ago.

"We thought it would take us six or seven hours. It took 18 to 19 hours. It was very, very cold. The sea was very, very rough with the channels. We came out of that experience... with a great amount respect for the reality of what actually happened," Nolan recalled at a Lincoln Ristorante Q & A with George Stevens Jr after the film was screened.

"Dunkirk" is based on the early stages of World War II, where thousands of British and Allied troops were trapped on the beach of Dunkirk with their backs to the sea surrounded by the enemy.

The director said the whole experience stayed with them for all this time before transforming into the war drama, which released this year in July.

"What would it really have been like to get on a boat and make a crossing like that but not be on holidays as we were, just going to hang around and prance for a bit - that just stuck with both of us over the years," he said.

The event was co-hosted by Barry Levinson. PTI RDS RDS