The Duchess of Cambridge, neé Kate Middleton, told schoolchildren she was finding her visit to the Somme "quite emotional," as she toured a new museum dedicated to those lost in the bloody battle.
Kate, 34, said the experience had been "very moving" as she chatted to British and French teenagers attending the centenary commemorations at Thiepval, France.
Princes William and Harry and Kate attended the centenary commemorations at Thiepval, France
She, Prince William and Prince Harry were touring a new visitors' centre at the Lutyens-designed Thiepval Monument to the Missing of the Somme with French President Francois Hollande.
The Royal party met 24 of the 600 UK, Irish and French schoolchildren taking part in the commemorations as part of a wider Anglo-French Somme educational programme organised by the British Council, which includes a week-long residential stay in the region.
Poppy Hodgson, from Hermitage Academy in Chester-le-Street and Neave Heaton, from Greenfield School in Durham, presented the Duke and Duchess with a binder of art, photography and history work produced by pupils taking part.
Prince Charles and David Cameron were also present
Poppy said: "She said it was quite emotional being here and that they were really enjoying their visit. She said it was very moving."
Prince Harry told students from St Paul's Community College in Waterford, Ireland, and Wolsingham School in County Durham: "It's important that you are here. There are all sorts of parts of history that are being forgotten.
"It's important for us to remember older history as well as more recent history. I'm actually quite jealous of you guys getting to spend five days here learning all about it. You will come back with a huge amount of knowledge."
Speaking about his visit to the top of the memorial, he said: "You get a real perspective of what happened, going over the top. None of us can imagine what that was like."
Kate wore a bespoke peplum lace dress
The Royal trio were shown around by the museum's vice-director Emilie Simon, taking in two dramatic 30metre-long murals showing the preparation for and first day of the 141-day battle by the Maltese-American cartoonist Joe Sacco.
"Look at the detail," remarked Kate, taking in the intricate artwork.
They also seemed fascinated by relics from the Trenches displayed under a glass floor, including shell cases, sections of barbed wire, boots and horseshoes.
They were also shown a German machine gun, captured by British troops as a Battle trophy on 26 September 1916. Their guide explained that one of the soldiers who seized the enemy weapon was declared missing the following day and his name is among the 72,000 on the Memorial to those whose remains were never found.
The Duchess of Cambridge revealed the experience had been "very moving"
William, Kate, Harry and Mr Hollande, who was guided around in French by the museum's director Herve Francois, also posed for photographs after officially opening the centre by unveiling a plaque.
The new visitor centre, which opened on June 1, will welcome 150,000 visitors each year.