Murphy, of course, is no stranger to Nolan, with the actor and director collaborating on no less than four films. There is no word on what role he will play, but he will be joining a cast that includes Tom Hardy (Lawless), Mark Rylance (Bridge Of Spies) and Kenneth Branagh (Valkyrie), plus newcomers Fionn Whitehead, Jack Lowden ('71), Aneurin Barnard (Citadel) and One Direction heart-throb Harry Styles.
Nolan will be directing from his own script, and co-producing with his wife and producing partner Emma Thomas. A longtime champion of traditional filming practices, he will be utilising IMAX 65mm photography, and releasing the film in multiple formats.
The film will tell the famous story of Operation Dynamo, the 1940 Allied military operation which evacuated over 300,000 soldiers from the British and French armies across the English channel after the German armies surrounded them.
A number of films have documented the event, including the film Dunkirk (1958) starring John Mills and Richard Attenborough, and more recently Joe Wright's Atonement (2007), which brilliantly visualised the turmoil on the beach in a grandstand tracking shot.
Filming on Nolan's effort is currently underway ahead of a planned 21 July 2017 release date.