Defence Secretary Sir Michael Fallon has said the "power of Allied force" is as relevant today as it was in 1917, as world leaders gathered to mark the centenary of a defining First World War battle.
Sir Michael, who will attend the event in France commemorating the Battle of Vimy Ridge, said national armies which work together were "continuing to make the world a safer and more secure place."
The ceremony will honour the sacrifices of Canadian forces and their British counterparts at the four-day battle of Vimy Ridge.
The Prince of Wales, France's President Francois Hollande and Canada's Prime Minister Justin Trudeau will be among those attending.
The Duke of Cambridge and Prince Harry will also join their father at the event which is being staged at a memorial on the battlefield in northern France, near the town of Arras.
Vimy Ridge, a decisive victory for the Allies against Germany, was important in the development of Canada's national identity as four military divisions from the nation fought together for the first time as the Canadian Corps.
The battle which began early on April 9 1917, was part of a larger British-led offensive, featuring Australian troops, known as the Battle of Arras which was a diversionary move to help a major French attack further south.
The Defence Secretary said: "Today, 100 years ago, British, Canadian and Australian troops served together with enormous courage and sacrifice, with thousands losing their lives in the Battle of Arras and the Battle of Vimy Ridge.
"The Battle of Arras saw the largest amount of Scottish units ever to have fought together, demonstrating once again their significance and contribution to the British Army, whilst the Battle of Vimy Ridge was a defining moment in Canada's history.
"The power of Allied force is as relevant today at it was in the spring of 1917, continuing to make the world a safer and more secure place."
During the ceremony Charles, President Hollande and Mr Trudeau will all speak and also lay wreaths at the Canadian National Vimy Memorial which honours all those from the Commonwealth country who died fighting during the First World War.
William and Harry - who have both served in the armed forces - will lay a pair of boots, some of the first of thousands that will be placed at the site by Canadian and French youth - representing almost 3,600 Canadians who died during the battle.
Before the ceremony Charles and his sons will tour some of the conflict's trenches that were reconstructed a few years after the end of the First World War.
In the evening, the royal trio will attend a reception.
They will meet young Canadians who attended the ceremony, athletes who have taken part in Harry's Paralympic-style Invictus Games for injured servicemen and women and veterans, and military personnel from some of Charles' Canadian regiments and military units.