Harry Styles was overcome with emotion at Dunkirk premiere

Harry Styles had to hold back tears the first time he watched his new war film Dunkirk.

The singer makes his movie debut in director Christopher Nolan's new film and admits the whole experience left him a bit of an emotional mess at the London premiere last week (ends14Jul17).

The 23-year-old singer, who plays soldier Alex in the World War II drama, tells BBC Radio One Breakfast Show host Nick Grimshaw, "The first time I watched it, because I hadn't seen anything and how he'd (Nolan) put the story together, I was more watching to see how the story was, and when I watched it at the premiere in London it got me a couple of times.

"There were a couple of emotional bits but I didn't know if I was allowed to cry at a film I'm in, but yeah it was really emotional. It's a very personal experience, even if you're watching it in a cinema full of people you feel like you're watching it on your own."

The One Direction star also told the radio host he felt a little out of his league when he first showed up to the set, and he was scared of the film's director.

"It was so overwhelming," he adds. "Trying to imagine something of that size, and when you actually see it, it's insane. And I was pretty in awe of him (Nolan) the whole time I was filming. I was a bit scared of him."

Dunkirk hits cinemas on Friday (21Jun17).