Dunkirk also stars Tom Hardy, Mark Rylance and Cillian Murphy and concerns the Dunkirk evacuation in 1940, and is told from three perspectives - the land, sea and air. Trapped on the beach with their backs to the sea they face an impossible situation as the enemy closes in.
In a recent interview with Entertainment Weekly, Nolan stated that he kept Styles out of trailers for Dunkirk because he didn't want to accidentally over-exaggerate his presence in the film.
'I think as hard as it would ever be on set, everyone was very aware of how, in comparison to what obviously people would have been through, this was nothing'.
Fans went wild over Harry meeting Harry, with one Twitter user writing: "Prince Harry with Harry Styles or should I say Harry Edward Styles with Prince Harry!" "I think what Harry does is extremely subtle because it's very real", he adds.
In addition to the star-studded cast, Britain's Prince Harry attended the film premiere, where he wore a blue suit and red and blue striped tie.
Dunkirk is due to open in cinemas on 21 July 2017.
Be sure to catch the film in glorious IMAX from next Friday.