Harry Styles has revealed he is contemplating retiring from acting after just one film.
One Direction singer Styles takes his first major acting role in Dunkirk, which is billed as a visceral portrayal of the historic events by Batman director Christopher Nolan.
But he told reporters at the world premiere in Leicester Square: "I'm thinking, what am I doing?
"I feel very lucky to be a part of Dunkirk… I'd do this one again but it may be one and done… I'd do this one again."
He continued: "I really enjoyed this. I've peaked too soon! There's nowhere to go."
Styles, who has just been overtaken by Niall Horan as the most popular member of One Direction on Twitter, was joined by Prince Harry on the red carpet.
Co-stars Tom Hardy, Kenneth Branagh, Cillian Murphy and Mark Rylance were also there, as well as veterans of the 1940 battle.
The Prince met with veterans from Dunkirk before he walked the red carpet, discussing the impact of war on mental health.
Nearly 340,000 soldiers were evacuated from Dunkirk between 27 May and 4 June 1940. It is thought that 68,111 were killed or captured.
Although Nolan has said he thought Styles was "perfect" for the part, the casting has raised eyebrows among some critics who regard it as a publicity stunt.
Meanwhile, co-star Rylance said he believed the message of the film was still relevant today.
He described an interview with PC Wayne Marques, who fought off three attackers in the London Bridge attack after being stabbed in the eye, as evidence of the spirit of Dunkirk.
"It moves me just to think of the heart of the man," he explained.
"I think it is a very important film to remind us of the potential in us when things are really bad, as they were in Dunkirk."
The movie was filmed on the beach at Dunkirk, and the space had to be checked for unexploded ordnances before the crew carried out controlled explosions.
Nolan described showing the movie to veterans as "the most daunting thing" he had ever done.
"I think it is one of the greatest stories in human history, not just British history," he said of the battle of Dunkirk. "The reason the story resonates and sustains is it's primal and elemental in its simplicity.
"I think it will resonate forever."
Dunkirk will be released in the UK on 21 July.