The young royals planted their own ceramic poppies at the Tower of London today, adding to a stunning sea of blood-red created to remember the Great War dead.
Each of the 888,246 flowers is a tribute to every life lost by the British or colonial forces in the conflict and has been created to mark 100 years since the day Britain went to war with Germany in 1914.
The Duke and Duchess of Cambridge were joined by Prince Harry at the Tower to officially unveil Paul Cummins' Blood Swept Lands And Seas Of Red.
It will grow over the summer and the last poppy will be planted on November 11, symbolically marking the end of the First World War in 1918.
From today each flower will be available to buy for £25, with proceeds shared among military charities.
The Duchess was heard to describe the scene as 'amazing' and 'spectacular' as she and the princes descended to take a walk through the field of scarlet that was once the Tower's dry moat.
After posing for photographers the royal trio were introduced to representatives of the charities set to benefit from the project.
Among them was Mark Taylor, known as Lofty, who is one of the Help for Heroes military charity's Band of Brothers.
Mr Taylor, 46, from South London, is receiving lifelong support from the organisation after suffering from acute Post Traumatic Stress Disorder following tours of duty over a ten-year career with The Princess of Wales Royal Regiment in Northern Ireland, Kosovo and Iraq.
Now an ambassador for the charity, he said: 'Kate was chatting about what an impact the poppies had.
'Prince Harry was trying to work out how much money they would raise for our charities and said what a great idea it was that they could use something like that, centred around the First World War, to benefit the charities that help injured servicemen now.'
William, Kate and Harry were also invited to each push a ceramic poppy into the ground after being handed them by one of The Lord Lieutenant's cadets.
Paul Cummins the Ceramic Artist said: 'I was inspired to create this installation after reading a living will by an unknown soldier who we think may have been from Derby. I approached the Tower as the ideal setting as its strong military links seemed to resonate.
'The installation is transient, I found this poignant and reflective of human life, like those who lost their lives during First World War. I wanted to find a fitting way to remember them'.
He came up with the idea of creating a 'sea' of poppies two years and was delighted when the Tower of London decided to bring his idea to life with the help of set designer Tom Piper.
Stage Designer, Tom Piper was in charge of planning how to make the poppies swoop and swirl across the Tower of London's grounds.
He said:' My role has been to work out how to place the ceramic poppies around the moat and hopefully create a few incidents where the poppies seem to become more fluid and the sea of red forms into a wave or pours out of a window . It is an amazing bit of military precision planning'
During the First World War, the Tower's moat was used to swear in over 1,600 men who had enlisted by the end of August 1914 at the recruitment station in the City to form the 10th Battalion of the Royal Regiment of Fusiliers, the so called 'stock brokers battalion' who fought for the duration of the war.
Flight Sergeant Cammeron Morante, 18, told the Duchess that his grandfather had been a medic with the Filipino army and had died at Pearl Harbour.
'I also chatted at length with Prince William about the RAF and he told me how much he was missing it. Kate also told me he was missing it too,' he said afterwards.
'Kate said that the poppies were wonderful.'
PO Cadet James Pavey added: 'The Duchess said what an impact the poppies had and it's true. When you are told how many people died in the First World War it doesn't really sink in but when you see the actual number of poppies it really brings it home to you.'
Before the royal party left they were introduced to a number of people involved in bringing the project to life, including the ceramic artist Paul Cummins.
Among the volunteers introduced to the Duke and Duchess and Prince Harry was Joan Clayton Jones, 72, from Susses.
She is the project's most prolific volunteer, having undertaken eight three and a half hour 'planting' sessions.
Mrs Clayton Jones' great uncle, Godfrey Leseelleur was killed on September 19 1918 at Ephy, just weeks before the end of the conflict, having survived the Gallipoli campaign.
She said: 'His death affected my family very personally. I was a lifelong friend of his sister, who died in her 90s, and I felt that volunteering to help with this wonderful project was my poersonal way of paying tribute.'
It is just one of the events taking place across the country in remembrance of those who died.
It came a day after the Royals joined political leaders and relatives of the fallen in Belgium to remember the sacrifices and losses exactly a century on from Britain's entry into the war.
A moving twilight ceremony at St Symphorien military cemetery near Mons was the highlight of a day of events in the UK and Belgium marking 100 years since the Great War's start.
The royals stood alongside Prime Minister David Cameron and counterparts from countries including France and German at commemorative events yesterday.
Mr Cameron said the Great War, which claimed millions of lives, including 750,000 from the British and Commonwealth, was 'unlike any other'.
Harry read a letter from Private Michael Lennon, of 1st Battalion the Royal Dublin Fusiliers, dated May 30 1915, who wrote to his brother Frank the day before he was due to land in Gallipoli.
He was killed in action on June 28 1915 - exactly a year after Archduke Franz Ferdinand was assassinated in Sarajevo, sparking the war.
In the letter, Pte Lennon wrote: 'Well Frank, I suppose we are for it tomorrow, if we don't get shelled on the way.'
Performances were heard from a children's choir conducted by Gareth Malone, as well as a recording of a collaboration between the London Symphony Orchestra and the Berlin Philharmonic Orchestra.
As the ceremony - narrated by TV historian Dan Snow - moved to a close, William, King Philippe of Belgium, Mr Cameron, and the German and Irish presidents laid flowers at the obelisk.
