Prince Harry joined Dunkirk veterans and stars of Hollywood for the premiere of the latest Christopher Nolan blockbuster chronicling the desperate World War Two evacuation of British troops.
Harry learned first hand about the massive 1940 operation to save hundreds of thousands of servicemen from advancing Nazi forces when he met men who had been on the French beaches.
Chatting to the old soldiers at Kensington Palace ahead of the premiere at the Odeon Leicester Square the prince, a former Army officer, quizzed the men, now in their late 90s, about their experiences.
Later he met the stars of Dunkirk at the premiere including leading British actors Tom Hardy, Mark Rylance and Kenneth Branagh, and Irish star Cillian Murphy.
Crowds packed the famous London square but the largest cheers were reserved for singer Harry Styles, whose appearance produced ear shattering screams.
At Kensington Palace Harry chatted to George Wagner, 96, from Litchfield near Birmingham, who was sent to Europe in late 1939 with the Royal Engineers, and like tens of thousands of others recounted how he seized an opportunity to get off the beaches.
He was given a private screening of the movie and said the sound of explosions brought back memories of the bombardment they faced as they tried to leave.
Mr Wagner said about the movie: "It's got bags of bangs, that's what worries me is the bangs.
"It just reminded me when we were just outside Dunkirk we were mortared as we were getting away. Then they started to shell us and then one or two planes started to have a go.
"I was down below deck, there were six or seven of us and we were soaking wet and naked, our clothes were in the engine room drying out."
The veteran later joined Harry at the premiere and walked the red carpet with the royal who was cheered and screamed at by the crowds.
Branagh, who plays Commander Bolton in the war movie, said: "The survivors who have seen the film were very generous in their comments about it in terms of what a film can do, although it can never be a real experience, they seemed to admire it.
"Harry also seemed very pleased this subject - Dunkirk - which he feels is a story which has faded from view, is something that the film can bring some attention to.
"George (Wagner) said he was there for three days and it's very, very hard to imagine how you cope with that. They were picked off like fish in a barrel.
"Churchill thought, hoped that 30,000 might be rescued but about 340,000 came back. It was still a dreadful loss of life and still not in anyway can it be construed as a victory - but still on the human level undeniably a miracle."