I believe 'Dunkirk' is one of the greatest casts, says Christopher Nolan

Nolan's film is based on true story of trapped Allied troops rescued from beaches of Dunkirk, 1940

Director Christopher Nolan has praised the ensemble cast of "Dunkirk" at the film's world premiere in London.

Prince Harry was a special guest at the event, which took place at Leicester Square, according to The Hollywood Reporter.

Nolan's WWII epic is a true story of trapped Allied troops being rescued from the beaches of Dunkirk in 1940.

Actors Cillian Murphy, Tom Hardy, Kenneth Branagh, Mark Rylance, Harry Styles were in attendance at the premiere.

"I passionately believe that this is one of the greatest casts put together for any movie," Nolan said, also offering his admiration to the 13 British army veterans who were in attendance at the premiere.

"One of the things I love about the film is that it doesn't set itself up to be important," said Branagh, who plays a Navy commander, adding that it is focused mainly on ordinary lives. "And it's all the more moving for it."

Styles, meanwhile, joked that Dunkirk may be his first and only film.

"Maybe I've peaked too soon," he said, adding that movie had made him "better at swimming.