The Princess Royal and her husband, Sir Timothy Laurence, were among the reduced number of people who attended the Dawn Service at Wellington Arch. The couple will later attend the Anzac Day Service of Commemoration and Thanksgiving at Westminster Abbey.
Today, April 25, marks the anniversary of the start of the World War 1 Gallipoli landings and is the national day of remembrance for Australia and New Zealand.
To mark the day, Her Royal Highness laid a wreath at both the Australian and New Zealand War Memorials and signed a book of remembrance.
Prince William also paid tribute to the “indomitable spirit” and “courage” of the Australian and New Zealand Armed Forces.
The Duke of Cambridge said in a statement: “This Anzac Day, Catherine and I join Australians and New Zealanders across the world to remember and honour the servicemen and women of the Australian and New Zealand Army Corps.
“Today we stand together to reflect not only on their sacrifices, but also their courage, sense of duty, and their famously indomitable spirit.
“Though many will still be unable to come together in person this year, we are heartened in the knowledge that Australians and New Zealanders will continue to commemorate those who have given so much for our freedoms.
“The Anzac qualities of endurance, courage, ingenuity, good humour and mateship are admired as fiercely as ever before.
“Lest we forget.”
They landed on Gallipoli on April 25, 1915, which became the date for Anzac Day.
Waves of Allied forces launched an amphibious attack on the strategically important Turkish peninsula.
This was key to controlling the Dardanelles straits, a crucial route to the Black Sea and Russia.
The plan, backed by the then-first lord of the admiralty Winston Churchill, was flawed and the campaign led to stalemate and withdrawal eight months later.
More than 60,000 Australians died during World War One.
The Australian Army wrote: “Anzac Day is one of Australia’s most important national commemorative occasions.
“It marks the anniversary of the first major military action fought by Australian and New Zealand forces during the First World War.”
Australian Prime Minister Scott Morrison also attended an event in Canberra.
Thousands of people across the country on Sunday morning attended dawn services to mark Anzac Day.
The day is to pay tribute to those who have served the country in wars, conflicts and peacekeeping operations.