King Charles says he wants to inspire a "sense of determination" to protect the environment, as details are announced of a TV documentary in which he will explain his philosophy of "harmony" and the need "to work with rather than against nature".

The King's Foundation says the feature-length TV film, provisionally titled Finding Harmony: A King's Vision, will be screened on Amazon's Prime Video early next year.

"Never has it been more important for the world to make a concerted effort to protect and prioritise our planet, and to restore our relationship with it," the monarch said about the project.

In the film, the King will reflect on his own decades of campaigning for sustainability.

The King said it was his "fondest hope that this film may encourage a new audience to learn about the philosophy of harmony - and perhaps inspire the same sense of determination it has given me to help build a more sustainable future".

The King has appeared in a behind-the-scenes BBC film about the Coronation, but this will be a more unusual approach in looking at his beliefs.

"For much of my life I have sought to promote and encourage ways we can work with, rather than against nature. In other words, to restore balance to our planet which is under such stress," said the King.

The one-off documentary will show how he believes humans are "part of nature, not apart from nature" and that a healthy connection with nature is at "the core of human wellbeing".

With examples from around the world, the documentary will show how the philosophy of harmony can be applied to agriculture, traditional craft skills, architecture and town planning.

"This film will, I hope, demonstrate just some of the remarkable work being done around the world to put harmony into practice, from the forests of Guyana to sustainable communities in India – and, closer to home, through the work of my King's Foundation at Dumfries House and Highgrove," said the King.

Director Nicolas Brown said there was a gap in knowledge about how the King's views on harmony had shaped his work.

"Remarkably few people around the world know the full depth of the King's lifelong battle to bring nature and humanity into harmony," he said.

Their cameras recorded the King's first harmony summit, held at Highgrove in Gloucestershire in July.

This brought together leaders of Indigenous people from around the world who shared their knowledge of how communities could live in tune with the natural world. Along with the King, they performed a fire ceremony at the start of the day, paying their respects to nature.

The King's views on harmony and the design of towns have also influenced thinking about creating a new generation of new towns in England.

With his Amazon documentary, the King will be the latest royal to appear on a streaming service. Prince William recently faced questions from Eugene Levy on Apple TV+ and Prince Harry and Meghan were in a Netflix series about their departure from royal life.

They have provided platforms for the royals to share their thoughts and opinions, but without a conventional interview format.

Kristina Murrin, chief executive of the King's Foundation, said the documentary would show the decades of the King's commitment to harmony, in a way that was "both moving and inspiring to see that journey committed to film".