Prince William is working on a secret project with esteemed environmentalist Sir David Attenborough and from the looks if it, the pair might be doing a film on saving the planet.

In a post on Instagram, the Duke of Cambridge simply shared a photo of chairs from a production set with their names on it. Prince William also used emojis like a pair of eyes, a film camera and the planet Earth in his cryptic post. 

It comes as the royal is set to do his very first TED Talk in October for a topic about climate change. The royal will speak at a whole-day conference that will also include guests like Al Gore, Mark Ruffalo, Chris Hemsworth, Don Cheadle and experts in the field of business, urban planning, and science and environment. 

The Duke of Cambridge will also debut a new documentary on environmentalism next month. Prince William: A Planet For Us All will run on ITV and will feature the royal's work in the last two years to make a significant impact for the environment. 

Prince William will likely talk about his initiative, the Earthshot Prize, in this documentary. The goal of this contest is to award people with smart, innovative and effective ideas that will help with the world's conservation efforts. 

According to Entertainment Tonight, this documentary also features Prince William's meeting with Attenborough a few months back. The teaser shows Kate Middleton telling the naturalist that her children are his biggest fans. 

Perhaps, the Instagram post is linked to the documentary's preview. Prince William likely sat down with Attenborough and his kids to watch the film together before it airs on television. 

Attenborough is a long-time friend of the royal family and is the same age as Queen Elizabeth. Prince Charles first met him with Princess Anne when they were kids and he was the controller of BBC.

Queen Elizabeth granted Attenborough his knighthood in 1985 for his work in the broadcast industry and for the environment. He also received the Order of Merit from the Queen in 2005. 

Prince William said that Attenborough is a national treasure. He regards the environmentalist as the most important person to affect his thoughts on conservation.

The Duke of Cambridge said that one of his joys as a child was to watch Attenborough's nature programs because learning from it was magical. The royal also influenced his children, George and Charlotte -- who are 7 years old and 5 years old, respectively -- to love Attenborough's shows.