The fellow dads have released a video for WildAid — the organisation that works to end illegal wildlife trafficking — in which they star alongside retired Chinese basketball player Yao Ming.
Scroll down to watch the video.
Suited and booted, William, David and Yao are filmed urging people not to buy rhino horn as they stroll onto the pitch of Wembley stadium in London.
"Imagine if all the people in the world could fit into one stadium," says ex-England football captain David at the start of the clip.
"Sadly, all the wild rhinos in the world can — with room to spare," says William as he emerges onto the sunlit pitch, looking dapper in a dark suit and maroon striped tie. "For some species, it's almost too late."
"But we can fill this stadium and many more if we can stop the illegal trade," says Yao. The camera then flicks to close-ups of computer generated rhinos roaming freely around the stadium.
"Ask your friends and family never to buy rhino horn," continues a perfectly-coiffed David as he smiles down at a baby rhino.
"And together we can save our wild rhinos," says William.
The trio then stop and William and David end the inspirational message with WildAid's slogan.
"When the buying stops," says William, "the killing can too," says David, as the final shot hovers over a stadium full of rhinos.
The video follows on from William and David's last recorded clip which they released in December. The Duke of Cambridge, 31, and father-of-four David, 38, teamed up with Yao to deliver a powerful message, in which they spoke about protecting wildlife such as elephants, rhinos and sharks for future generations.
"As a father, I want our children to know that rhinos are not just a picture in a book," says William in one shot, while David adds, "I want our children to be able to swim with sharks, not just eat them in a soup."
The trio met in September 2013 to film the two messages that aired globally. WildAid's mission is to end the illegal wildlife trade — estimated to be worth six billion pounds — by reducing consumer demand and raising public awareness.