The Prince of Wales will make a passionate plea for urgent action to save our oceans "while we still have the chance", after joining forces with Sir David Attenborough to highlight the issue.
Prince William appears alongside the legendary naturalist in a short film to promote his new Oceans movie.
He is seen joking with Sir David as the 99-year-old wildlife presenter demonstrates putting on one of his first diving helmets, with William telling him, "Don't put it on, you won't get it off David!"
The clip has been shared ahead of the heir to the throne's trip to Monaco on June 8, where he will deliver a landmark speech urging government and business leaders to take action to protect our seas.
The Prince is expected to say: "Halfway through this decisive decade, I call on all of you to think big in your actions. Let us act together with urgency and optimism while we still have the chance."
"There should be no doubt that this speech is The Prince of Wales calling for action to save our oceans now," said a Kensington Palace spokesman. 2The world is watching. This is him using his platform to call for more to be done sooner rather than later."
In the latest example of how the future King's role as a global statesman is evolving, William will join world leaders including President Emmanuel Macron of France and Costa Rica's President Rodrigo Chaves Robles and Prince Albert II of Monaco at the Blue Economy and Finance Forum.
Before making his speech, the Prince will also meet winners and finalists of his Earthshot Prize Awards, as they showcase the solutions for some of the biggest problems facing the oceans.
Since its inception in 2021, finalists in the Earthshot Prize's Revive Our Oceans category have collectively protected and restored more than 20,000 square kilometers of ocean and saved, reduced or recycled 2.5million tonnes of water.
They include Earthshot Prize winners Coral Vita, who have pioneered a new way to grow coral up to 50 times faster than in nature.
Prince William is said to be "laser-focused" on the issue as time runs out to reach a global target to protect 30 per cent of the land and sea by 2030. So far, just three per cent of the ocean has been protected.
Oceans cover 70 per cent of the Earth's surface and generate half of the world’s oxygen while regulating the climate and providing food for more than three billion people worldwide.
But rising sea temperatures, pollution and overfishing all threaten their fragile ecosystems.