Warner Brothers has unveiled the official trailer for the highly-anticipated forthcoming WWII epic Dunkirk, directed by Christopher Nolan.

The film is written and produced by Nolan and focuses on the events of Operation Dynamo on the French beach of Dunkirk, where a group of Allied soldiers was surrounded by German forces during the Battle of France.

The film stars Tom Hardy and Mark Rylance and marks the official acting debut of former One Direction member Harry Styles.

Enjoy the trailer above and look for the film to hit theatres July 21.