The heir to the throne has attended screenings of the broadcaster’s documentaries privately, while Sir David has been a champion of Prince William’s environmentally focused Earthshot Prize since its inception.
Now taking a lead from the 99-year-old host of Ocean and Planet Earth, the prince said his new series “reminds people that there are still wonderful parts of the world and there is still hope, and there’s still amazing work being done”.
He surprised those attending the screening of the series when he walked into a central London hotel and sat with journalists to watch the first three episodes.
Guardians will focus on how the work of rangers – who protect endangered animals – has become significantly more risky. Around 1,400 rangers have died in the past decade.
“This is now one of the most dangerous jobs on the planet,” the prince told reporters.
“It shouldn’t be. Protecting the natural world shouldn’t be that dangerous.
“Being a soldier, a police officer, the emergency services – these jobs are dangerous, people put their lives on the line.
“I don’t think people realise it’s the same for these guys and girls around the world.”
He attributed the increased threat to “community conflicts or civil wars, or illegal fishing, or poaching – whatever it might be is just spreading further and further across the globe”.
A friend said the prince turned up to emphasise the importance of the series to him on a personal level.
“The project was driven by him,” the friend told the BBC. “He wanted to show the incredible work rangers do for people around the world.”
Each episode will feature an on-screen introduction by Prince William, who also appears in a trailer for the project.
The prince also spoke about the challenge of recruiting the next generation of rangers.
He said: “They ask, why would I do that? Why would I go and risk my life to do that? No one seems to notice and no one seems to care. I’m not necessarily paid enough, I’m not valued enough by society.”