Forget David Beckham failing to get the sword out of the stone in Guy Ritchie’s King Arthur turkey, the movie cameo of the year goes to one Harry Styles, making his cinematic debut as Alex, one of a 1,300 strong unit of soldiers stranded on the Dunkirk beaches in Christopher Nolan’s hugely anticipated summer blockbuster about the legendary WWII retreat. This week he spoke to Little White Lies about the experience, which involved “gruelling” hours of filming in water which anyone who’s ever tried to rescue a brick from the bottom of a swimming pool in their pyjamas will relate to.

Harry Styles: all at sea

You picture our Harry turning up on the Dunkirk set on his first day in films decked out in his shiniest soldier outfit that his mum has ironed specially, only to be unceremoniously dumped in a water tank and told to doggy paddle for his life. “A week before we started filming,” ho told Little White Lies, “Emma [Thomas, producer] called me and said, ‘By the way, I forgot to ask… you can swim, right?’ It was a relief to know I could because there was so much swimming involved. However much you train for it, filming in the water for an hour in full clothes is a grueling experience.”

Harry Styles: Dunkirk’s three plot angles

Nolan’s movie tackles the events of Dunkirk via three separate strands, following the action of the air force, the land armies and the flotilla of boats gathered to save the soldiers on the beaches. Early reports suggest there’s surprisingly little dialogue in the film, and Harry also hints that the film is driven by emotional portrayals of survival. “From a character point of view, the story is stripped back to basic instinct,” he said. “It’s all about that survival instinct, and how different people reacted to the situation in different ways. So you have clashes and tension between different characters and that intertwines with the land, air and sea theme.”

Styles on Nolan

According to Harry, Nolan was a total workaholic on set. “The biggest thing I learned from making this movie is that Chris Nolan doesn’t sit down,” he said. “He leads by example, so any time there’s a break given it’s because he knows everyone else needs one. It makes it really hard to complain because you know he’s been there longer than you, you know he’s the first one there and you know he’s going to be the last one to leave. For him it’s all about making the project the best that it can be, and that’s infectious.”

Other cast members praised Nolan’s immersion into the project too, encouraging lead actor Fionn Whitehead, who plays an army private called Tommy, to watch war film The Thin Red Line and other cast members to read Joshua Levine’s book The Forgotten Voices Of Dunkirk. “That was brilliant,” said actor Tom Glyn-Carney, “because you really get a sense of all these different perspectives, of what these men were hearing and seeing and smelling.”

Read more about Dunkirk on our Trailer, Cast And Release Date blog.