The Prince of Wales, the Duke of Cambridge as well as Prince Harry are to join more than 25,000 people in northern France to mark the centenary of a defining World War One battle.
The four-day battle of Vimy Ridge saw the deaths of 3,598 Canadian forces.
Princes William as well as Harry will lay a pair of boots as part of a tribute to those killed near the city of Arras.
Canadian Prime Minister Justin Trudeau as well as French President Francois Hollande are among the others attending.
William, Harry as well as the Prince of Wales will walk from the trenches of the former battlefield before taking part from the memorial.
Vimy Ridge was an engagement during the Battle Of Arras, which lasted via 9 April to 16 May 1917 as well as involved British, Canadian as well as Australian troops.
The fighting saw the highest concentration of Scots involved in any WW1 campaign. with 18,000 Scottish deaths, among the 159,000 allied troops killed, wounded or missing.
The ridge, which is actually about 108 miles (175 km) north of Paris, was captured by Germany early from the war as well as transformed into a strong defensive position.
The attack on 9 April sparked four days of intense fighting, until Canadian forces under British command retook the heights overlooking the Douai Plain, which was still occupied by the enemy.
UK Defence Secretary Sir Michael Fallon, who will also be at the event, said the “power of Allied force” is actually as relevant today as in 1917 as well as they are “continuing to make the earth a safer as well as more secure place”.