Meghan Markle appeared close to tears during a moving Anzac Day dawn service where fiancé Prince Harry honoured New Zealand and Australia's war dead.
During the poignant event staged as the sun's rays broke over the London skyline, Ms Markle looked emotional as the hymn Abide With Me was sung by thousands gathered at the New Zealand war memorial.
The American actress was making her first appearance at a service marking Anzac Day - April 25 - the anniversary of the start of the First World War Gallipoli landings, and a national day of remembrance for Australia and New Zealand.
Harry, a former army officer who served for 10 years in the forces, led the nation's tribute to New
Zealand and Australia's war dead by laying a wreath during the service at one of a group of metal crosses near Wellington Arch in central London.
A handwritten note from the prince, attached to a wreath of red roses, read: "For all those who have made the ultimate sacrifice in pursuit of our freedom. Thank you. Harry"
Ms Markle may not yet be a member of the Royal Family but she has attended a large number of official events in the run-up to her royal wedding on May 19.
The US actress, who wore a grey coat and large brimmed hat, passed a cultural milestone when she, and Harry, were welcomed by Te Ataraiti Waretini from Ngati Ranana - the London Maori Club - with a traditional hongi, the soft pressing of noses and the sharing of each other's breath.
There were other Maori cultural elements during the dawn service including a haka performed at the end, a longer version of the one displayed by the famous New Zealand rugby team the All Blacks before matches.
Ms Waretini said about Meghan: "She was amazing. I'm not sure if it's her first time at a Maori ceremony but she did very very well.
"It was really lovely to meet her and share the breath of life and share our culture with her and Harry."
Trevor Mallard, speaker of the New Zealand House of Representatives, gave the address during the dawn service and told the Kiwis and Aussies: "Today we remember 100 years have passed since the final year of the First World War. We honour the service of those who came half way around the world.
"Some with a deep conviction that they were fighting for king and empire, some fighting for peace and justice, others were young lads who saw an opportunity for adventure - none could have foreseen the hell on the frontline and in the trenches."
He added: "Today in thousands of communities throughout Australia and New Zealand people have come together to acknowledge and pay tribute to those who left our shores and particularly to commemorate those who gave their lives for our freedom."
Thousands of Anzac troops - Australian and New Zealand Army Corps - died in the ill-fated 1915 Gallipoli campaign.
Waves of Allied forces launched an amphibious attack on the strategically important Turkish peninsula, which was key to controlling the Dardanelles straits, the crucial route to the Black Sea and Russia.
But the plan backed by Winston Churchill, then first lord of the admiralty, was flawed and the campaign, which faced a heroic defence by the Turks, led to stalemate and withdrawal eight months later.
Its legacy is the celebration of the "Anzac spirit" - courage, endurance, initiative, discipline, and mateship - shown by the Antipodean troops and today the Anzac Day service in London has become an important moment for thousands of New Zealanders and Australians.
During the service prayers were read by young school children and the Last Post was sounded by a bugler before a minute's silence was observed by all.
After the service Harry, Meghan and dignitaries walked the short distance to the Australian war memorial where the prince laid another floral tribute.
Sir Jerry Mateparae, the high commissioner of New Zealand, who attended the service said later that Ms Markle was talked through the Maori elements of the service so she understood their significance and importance.
He added: "She was very interested, also it's her first Anzac service so we were explaining what it meant to us and the Australian memorial, so for her it was a new experience.
"The thing that was special in a way was the prayers led by the children and certainly Prince Harry and Ms Markle were impressed by the young people and the confidence of their delivery but also the way they conducted themselves."