EXCLUSIVE: We have first footage of a 21-year-old King Charles III (then just a humble Prince) delivering one of his very first speeches about what was to become one of his biggest passion projects, the environment.

The footage from more than 50 years ago comes via Prime Video’s Finding Harmony: A King’s Vision doc, which launches Friday and is narrated by Kate Winslet.

In the footage, which can be watched above, a young Charles can be seen addressing a room with surprising passion as he bemoans the “horrifying effects of pollution in all its cancerous forms” and the “growing menace of oil pollution at sea.”

At the time, public discussions about the environment were rare, notes narrator Winslet.

In the clip, the now-King Charles III can be seen reacting to the vid. “I remember being profoundly concerned about all this,” he says.

The doc launches Friday globally and charts how The King’s Foundation, headquartered at its flagship regeneration project Dumfries House in Ayrshire, Scotland, has sparked a global ‘Harmony’ movement. From sustainable textiles and food production, to urbanism, community regeneration and traditional skills, the film documents how the model of sustainable community regeneration at Dumfries House, pioneered by The King’s Foundation, has inspired similar projects around the world.

The feature had its premiere last week at Windsor Castle, attended by the King and Queen along with stars like Winslet, Judi Dench and David Attenborough. It comes with Amazon docs firmly in the spotlight due to the controversial Melania movie.

Finding Harmony was produced by Passion Planet. MD David Allen told Deadline: “We jumped at the opportunity to tell the grand sweep of a King’s life through his commitment to the power of the natural world. Working with The King’s Foundation and Prime Video to unpack this philosophy of Harmony,  I really believe the film’s uplifting messages of hope will connect with people far and wide. We’re incredibly proud of the finished film and our team that have worked so hard to make this possible.”