Christopher Nolan asked Steven Spielberg for advice before filming 'Dunkirk'.
The 47-year-old director might be a Hollywood heavyweight in his own right, but even he had to turn to the likes of filmmaking legend Spielberg before embarking on his journey into Second World War project 'Dunkirk', as he wanted tips from the man who had achieved success with similarly themed movie 'Saving Private Ryan'.
Spielberg, 70, said: "Knowing and respecting that Chris is one of the world's most imaginative filmmakers, my advice to him was to leave his imagination, as I did on 'Ryan,' in second position to the research he was doing to authentically acquit this historical drama."
As part of his research into making the movie - which starred Tom Hardy, Kenneth Branagh, and One Direction's Harry Styles in his acting debut - Christopher sat down to watch 'Saving Private Ryan', and learned which elements he wanted to be different.
He said: "The film has lost none of its power. It's a truly horrific opening, and there are later sequences that are horrible to sit through. We didn't want to compete with that because it is such an achievement. I realised I was looking for a different type of tension."
Instead, Christopher wanted "suspense", and said his goal was to create "physical jeopardy".
He added: "I needed suspense, and the language of suspense is one where you can't take your eyes from the screen. The language of horror is one where you hide your eyes. You're looking away. It's a different form of tension. We constructed our set-pieces not around violence, not around blood, but around physical jeopardy."
Christopher - whose impressive directing credits also include 'The Dark Knight', 'The Dark Knight Rises', and 'Inception' - doesn't even think 'Dunkirk' is a war film.
He told Variety magazine: "I didn't view this as a war film. I viewed it as a survival story."