The Duke of Cambridge has spoken passionately of his love of conservation - and how becoming a father for the first time has made him more protective.
In an hour-long documentary, the first to be filmed since the birth of his son Prince George, William told of the importance of the "legacy" that he wishes to leave behind for future generations.
William, wearing a polo shirt emblazoned with the logo of UK-based African wildlife conservation charity Tusk Trust of which he is royal patron, was interviewed at Kensington Palace by documentary film maker Jane Treays, soon after George was born in July.
He appeared moved, not only by footage of conservation workers in Africa but also by a video of his late mother Diana, Princess of Wales, seen on an anti-landmine visit to Angola. He spoke of Diana's "excitement and passion" at the charity work she undertook, and said: "I never realised quite how much of an impact she had."
While his conservation work is not "obviously related" to the causes championed by his mother, William stressed that both were dedicated to "helping the needy and the vulnerable".
His love of Africa led William to fly there to propose to Catherine, as he was comfortable there and the choice "felt appropriate". He told the ITV programme: "Catherine probably thinks I'm completely Africa potty. But she understands what it means to me, and my love of conservation. But I think she wishes I didn't go on about it as much as I do!"
During the programme, he was shown images of rhinos with their horns removed by poachers and appeared close to tears at times. "Seeing a badly injured animal such as a rhino, seeing its horn, it's come, for me, to symbolise human greed," said the Prince, who added: "I feel a real protective instinct, also now probably more so now that I am a father, which is why I'm getting quite emotional about it."
William said he hopes he will pass on his love for endangered animals on to his young son, by "whispering sweet nothings in his ear" about them, and filling his nursery with toy elephants and rhinos. He also hinted that he would one day take Prince George to Africa.
"The last few weeks, for me, have been a very different emotional experience, something I never thought I would feel myself," explained the Prince. "It's only been a short period, but a lot of things affect me differently now. It's a daunting task when you realise that you want to pass on things to your son, and suddenly you start to realise 'wow', there's stuff you want to safeguard for the future. I've always believed it, but to actually really feel it too, it's coming through quite powerfully now."
The documentary, Prince William's Passion: New Father, New Hope, was broadcast in the UK on Sunday and will be shown on CNN on Monday.