King Charles believes that the future of the human race is lying in the hands of state leaders who need to give their "full backing" to environmental issues.
The BBC star believes that Queen Camilla, who has never shied away from his love for the natural world will continue to offer his full support.
Sir David, appeared on a special BBC One programme alongside Kirsty Young to celebrate the Monarch just hours before he is officially crowned King Charles III, alongside his wife, Queen Camilla.
During the episode, the naturalist who will celebrate his 97th birthday on Monday said the King "very clearly" understood the importance of the natural world "right from being a small child".
He told Kirsty: "When he became prominent and an adult, he took a strong line at a time when nature conservation was regarded as being slightly specialist.
"But he realised what it was about and he was mocked actually because he said 'Trees are so important I feel like talking to trees'.
"But in fact, he was absolutely right and the world has come to see the world as he saw it."
Sir David added: "The fact is 20 or 30 years ago, it really was sort of oddball to a lot of people.
"But now everybody realises that the future of humanity is dependent upon a healthy natural world.
"The way ahead demands that leaders of the state should actually give their full backing and I'm quite sure that as King he will lead this country in a very important way."
Reflecting on his first meeting with the then Prince Charles, who was just nine, during a visit to the BBC studios, Sir David explained: "I had just come back from New Guinea with a load of animals which were going to the London Zoo.
"But I had a pet cockatoo and I was asked to bring it to the studios, which I did.
"Dear little Cocky is sitting on his (Prince Charles's) hand but in fact, they have a very powerful beak and a very powerful bite and although I was fairly confident about Cocky, he could actually have removed his little finger but all was well and it was a very happy occasion."
The broadcaster who has a long-standing love for the Monarchy said he will be looking forward to the "whole panoply of the military, the parade, and, of course, the ceremony itself", which he believes will be "deeply moving".
