The Prince of Wales and Duke of Cambridge have joined forces to record a video message calling on the world to act now to save endangered animals like rhinos, elephants and tigers.
Charles and William's joint plea is the beginning of a week of wildlife conservation activities by the royal men, which will culminate in them attending the London conference on the illegal wildlife trade.
The royal duo even speak in a range of languages, from Mandarin and Arabic to Swahili and Vietnamese, to get their message across to their target audiences.
However, William has faced criticism for launching the campaign a day after enjoying a hunting trip in Spain with Prince Harry.
The pair were hunting wild boar and stags on a private estate. There is no suggestion that the hunt breaks the law in any way.
A spokeswoman for Animal Defenders International said it was "absolutely shocking" that the Royals should take pleasure in shooting animals.
In the campaign's new video William, president of WWF-UK, says: "We have come together, as father and son, to lend our voices to the growing global effort to combat the illegal wildlife trade - a trade that has reached such unprecedented levels of killing and related violence that it now poses a grave threat not only to the survival of some of the world's most treasured species, but also to economic and political stability in many areas around the world."
The Prince and Duke have worked together before to raise the issue of animal conservation and William is royal patron of the wildlife conservation charity Tusk Trust, and last year formed the umbrella body United For Wildlife to help tackle the threat to the world's endangered species.
He said: "This year, I have become even more devoted to protecting the resources of the Earth for not only my own son but also the other children of his generation to enjoy.
"I want them to be able to experience the same Africa that I did as a child."
His father highlights how "organised bands of criminals" are feeding an insatiable demand for animal products, much of it destined for consumers in Asia.
Spelling out the cost in animal lives, Charles said: "More than 30,000 elephants were killed last year, amounting to nearly 100 deaths per day.
"In the past 10 years, 62% of African forest elephants have been lost. If this rate continues, the forest elephant will be extinct within 10 years. A rhinoceros is killed every 11 hours.
"As recently as 100 years ago, there were as many as 100,000 wild tigers living in Asia. Today, there are believed to be fewer than 3,200 left in the wild."
The father and son sit side by side during their message, recorded at Clarence House in November, and the video features images of the carcasses of animals killed by poachers but also others running free on grass plains, as well as Charles and Camilla in Africa.
The video ends with Charles saying the phrase "Let's unite for wildlife" in Arabic, Spanish and Mandarin, while William says the same words in Vietnamese and Swahili
Charles will give a speech at the London Conference on the Illegal Wildlife Trade being hosted by the Government at Lancaster House on Thursday. William will also attend and it will be hosted by the Prime Minister.
World leaders will discuss the threat to endangered species and attempt to agree a more co-ordinated global response to the issue.
The evening before, William will give a speech at a Natural History Museum reception marking the start of the London Conference and during the day will attend a meeting of his United for Wildlife body at the the Zoological Society in the capital.