Prince William will be attending New Zealand commemorations of the 100th anniversary of the Battle of Passchendaele in Belgium on 12 October.
The Prince will be attending on behalf of his grandmother Queen Elizabeth alongside Princess Astrid of Belgium, who will be attending on behalf of her brother King Philippe.
The battle of Passchendaele was a three month campaign from July 1917 where British commanders spent months attacking German forces holding the ridge overlooking the Belgian city of Ypres.
During the battle New Zealand forces had to climb from sodden trenches through a muddy quagmire that had been produced by weeks of rain.
Within hours on October 12 1917, 843 New Zealand men lost their lives and almost 2000 were injured.
"It is fitting that the Duke of Cambridge will be there to mark 100 years since the battle and to recognise an important part of New Zealand's story," caretaker Prime Minister Bill English says.
"I am also pleased that Princess Astrid will attend as the centenary provides an opportunity for Belgium and New Zealand to remember the events which so profoundly affected both our nations and which tie us together today."
Minister Nick Smith and Speaker of the House David Carter will join Prince William and Princess Astrid in Tyne Cot, Belgium for the commemorations.