The dad-of-three had planned to make an appearance at The Earthshot Prize Innovation Summit in New York on Wednesday, but regrettably pulled out owing to his grandmother's mourning period.
WATCH: Prince William, Prince George and Princess Charlotte leave with the Queen's coffin
In a pre-recorded video, the royal shared a touching message in which he mentioned the late monarch. William gushed: "Although it is the saddest of circumstances that means I cannot join you in person today, I am pleased to be able to join you in video form as you gather in New York for the Earthshot Prize Innovation Summit.
"During this time of grief, I take great comfort in your continued enthusiasm, optimism and commitment to The Earthshot Prize and what we are trying to achieve."
Prince William is mourning the loss of his grandmother
Paying tribute to Her Majesty, the 40-year-old added: "Protecting the environment was a cause close to my grandmother's heart, and I know she would have been delighted to hear about this event and the support you are all giving our Earthshot Finalists – the next generation of environmental pioneers."
Prince William's heartfelt message comes ahead of the hotly anticipated Earthshot Prize finals which will take place in December this year.
The Prince and Princess of Wales are expected to travel to Boston where they'll announce the second annual cohort of Earthshot Prize winners. In anticipation, William added: "We look forward to seeing you all very soon."
The royal attended Her Majesty's state funeral at Westminster Abbey
The Earthshot Prize has been inspired by President John F. Kennedy's 'Moonshot' programme in the 1960s, which urged millions of people to support the US space programme.
It is based on five 'Earthshot' goals: Protect and restore nature; fix our climate; clean our air; revive our oceans and build a waste-free world.
William and Kate attended the Earthshot Prize awards ceremony in 2021
Five £1 million prizes will be awarded each year for the next ten years, providing at least 50 solutions to the world's greatest environmental problems by 2030.
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