The Dark Knight: Paul Kane/Getty Images; Dunkirk: Warner Bros. Entertainment, Inc.

Harry Styles is set to make his film debut in Dunkirk this month, but his celebrity stature didn't phase Christopher Nolan! As the director made his press rounds in promoting the movie, he revealed that he never heard of Styles prior to casting him. The decision also reminded him of a certain Heath Ledger.

"I don't think I was that aware really of how famous Harry was [before casting].I mean, my daughter had talked about him," Nolan said via The Hollywood Reporter. "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."

As for the Heath Ledger comparison? Don't bring your claws out just yet, DC fans, because the director had a valid point. Nolan explained to Entertainment Tonight:

"When I cast Heath Ledger as the Joker [in The Dark Knight], it raised a lot of eyebrows and caused a lot of comment," Nolan said. "I have to trust my instincts, and Harry was perfect for this part. What I'm hoping for, when people see the film, is I'm hopeful that they won't miss what he's done, because it's very subtle, very truthful and real. I wasn't giving him a sort of flashy thing to do. But it's really important what he does in terms of what it says, I think, about human nature and what people do in different situations, and I think he pulled it off with incredible grace and reality. And that as a director, that's what you're looking for."

Look out for Dunkirk, Nolan's first film since 2014's Interstellar, in theaters on July 21. While Harry Styles clearly doesn't have a major role in this film, but why not promote him even more with this classic interview with his former One Direction pals at the This Is Us film premiere: