Thats our boy.
Many people assumed that Harry was cast due to his huge celebrity status, and the fact that he would bring a whole new audience of teenagers to watch a war movie (which, let's be real, that did happen).
However director Christopher Nolan explained the real reason why he cast Harry, and it's unexpected: his face!
Chatting with The Daily Mail, he said, "He has an old-fashioned face ... the kind of face that makes you believe he could have been alive in that period. Harry's character's very un-glamorous. It's not a showboating role. Harry sent in a tape, and we liked the tape. And he joined the workshop, and that was that. It was a really old-fashioned process - and Harry's features, ability and demeanor fitted right in."
Christopher continued, "Harry shied away from being a 'star' in it. He's a humble guy who didn't want attention. He enjoyed the idea of not carrying it; that he was part of an ensemble. Like the soldiers they played, the actors were all in it together and supported each other very well...Harry's very talented. I've no idea whether he wants to pursue acting, but he's a natural."