The minute-long video features archive footage of the 94-year-old broadcaster traversing the globe as a young man.
The documentary film, A Life On Our Planet, is being released alongside a book detailing Sir David’s career and the decline of the planet’s environment and biodiversity he has observed first-hand.
In the video, he says: “Wherever I went there was wilderness. Sparkling coastal seas, vast forests, immense grasslands. You could fly for hours over the untouched wilderness.
“And there I was, actually being asked to explore these places and record the wonders of the natural world for people back home.
“To begin with it was quite easy. People had never seen pangolins before on television, they had never seen sloths before, they had never seen the centre of New Guinea before.
“It was the best time of my life.”
The film, which serves as Sir David’s witness statement for the natural world, will premiere in cinemas on September 28 before launching on Netflix in the autumn.
It was created by natural history filmmakers Silverback Films and global environmental organisation WWF.
Cinema showings will feature a conversation between Sir David and Monty Python star Sir Michael Palin, who shares a love of the natural world.
Sir David’s book, A Life On Our Planet: My Witness Statement And Vision For The Future, will be published in the autumn.
He previously said of it: “This book records some of the dreadful damage mankind has already wrought upon the natural world and the real and imminent danger that things could get much, much worse if we do not act now.
“But it is also a hopeful book – it offers a different future.”
