All eyes have been on the former One Direction star in the run-up to the film’s release and the actors, who play Mr Dawson and George, have nothing but praise for their co-star.
Speaking to HuffPost UK ahead of Dunkirk’s release, Barry said of Harry: “He’s taken it all very, very well. I’ve heard some questions he’s been asked.
“You’ll see when you watch the movie that he was chosen for this for a reason.”
Mark then joked: “Barry thought all the girls were calling ‘Barry’ on set, he didn’t realise they were calling ‘Harry’.
“I thought Harry took the bullet for you, to be honest with you because otherwise you would have been locked in your hotel room.”
“I couldn’t do what I wanted to because there were all these people around me,” Barry quipped.
‘Dunkirk’ is one of the most hotly-anticipated releases of the year and sees Christopher Nolan assemble an all-star cast to tell the story of the World War II evacuation.
Director Christopher previously claimed that he had no idea just how famous Harry was when he cast him for the part of Alex.
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.”
‘Dunkirk’ arrives in UK cinemas on Friday 21 July.