The prince, who served in Afghanistan and Iraq, wore his military medals and his Knight Commander of the Royal Victorian Order star over his necktie as he placed a wreath of red poppies at the memorial at Hyde Park Corner, London.
Anzac Day commemorates the first major battle involving Australian and New Zealand forces during World War One. It has been honored in London since the first anniversary of the Anzac landings at Gallipoli in 1916, when King George V attended a service at Westminster Abbey.
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The somber outing comes just one day after the royal’s appearance at the London Marathon, where he presented prizes and came to the rescue of former Olympian Sylvia Disley, who tumbled on stage during the medal ceremony. The 86-year-old, who won bronze in the 4x100 relay at the 1952 Olympics, is the widow of London marathon co-founder John Disley. She appeared uninjured by the fall and Harry held her hand as he led her off the stage after the ceremony.
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Anzac Day is an important tradition for the royal family. When Prince William and Princess Kate were in Canberra on the last day of their tour of Australia in April 2014, they rose before dawn to take part in the service at the country's national war memorial.
And last April, Harry and his father Prince Charles traveled to Turkey for the 100th anniversary of the Gallipoli campaign during World War I.
The poignant early morning service began on Monday with the sound of a putatara conch shell trumpet playing a lament, followed by the band of the Grenadier Guards playing the hymn, "Abide With Me."
Alexander Downer, Australian high commissioner to the U.K., told the gathering of thousands of people on the edge of Hyde Park, "When we reflect on Anzac Day we imagine the Gallipoli landings, what it must have been like, at dawn on the water, in sight of that rugged shoreline – and a collectively held breath, a leaden silence about to be broken."
Harry also attended a parade at the Cenotaph, a war memorial, where he laid a tribute on behalf of his grandmother, Queen Elizabeth. He then he took part in a service of commemoration and thanksgiving at Westminster Abbey.