Apparently, being a thrice Oscar nominated filmmaker does not mean you are always completely up to date with all pop culture developments. In fact, Christopher Nolan barely knew who Harry Styles was before casting him in his first movie 'Dunkirk', and only really heard his name through the kids.

Harry Styles on the set of 'Dunkirk'Harry Styles on the set of 'Dunkirk'

If you were wonderng whether or not the One Direction star won his role solely because he's super famous and would appeal to a young demographic, you'd be mistaken. Christopher Nolan, who wrote and directed forthcoming World War II thriller 'Dunkirk', insists that his focus was only on Harry's proficiency as the character of Alex.

'I don't think I was that aware really of how famous Harry was', he told the Hollywood Reporter. 'I mean, my daughter had talked about him. My kids talked about him, but I wasn't really that aware of it. So the truth is, I cast Harry because he fit the part wonderfully and truly earned a seat at the table.'

Watch the trailer for 'Dunkirk' here:

Styles doesn't seem to have a particularly large role in movie, despite the fact that his name stands out alongside stars the likes of Tom Hardy, Cillian Murphy, Kenneth Branagh and Mark Rylance. He's also not the only pop superstar to have gone into serious acting in recent years.

Rihanna had memorable roles in both 'Battleship' and 'Home', and is set to appear in 'Valerian and the City of a Thousand Planets' and 'Ocean's Eight'. Taylor Swift was in 'The Giver', Paul McCartney in 'Pirates of the Caribbean: Dead Men Tell No Tales' and Lady Gaga in 'American Horror Story'. Performing on stage and acting generally seem to go hand in hand.

Meanwhile, Mark Rylance has earned favour in his household for starring with Styles. '[My niece] was just more excited than anything I've ever done because I was going to be acting with Harry Styles', he said. 'I went up in her estimation. I won the Harry!'

More: Harry Styles' acting skills praised by co-star

'Dunkirk' will be released in theatres on July 21st 2017.