Prince William opened up about the one special reason he wanted to do the documentary, Prince William: A Planet for Us All. Set to air on ITV in the U.K. on Oct. 5, the film charts the Duke of Cambridge's conservation efforts in the last two years.

The second in line to the British throne said that, while he was inspired by environmentalists like his father, Prince Charles, and grandfather, Prince Philip, to do something for the Earth, his actual motivation is for one very important person: his first-born son, seven-year-old Prince George.  

According to People, Prince William said that he doesn't want Prince George to wonder what his dad did to help with conserving the Earth's resource. The Duke of Cambridge fears that if George asks this question in 20 years then it means that the adults have been too late to save the planet.  

Prince William said that it became his newfound mission to do conservation efforts when he became a father. As with Prince Charles, the Duke of Cambridge believes that the younger generation deserves to have a better world from the older generation. The royal shared that he feels this is his duty, and the public's "collective responsibility" to give the children a liveable planet. 

On Saturday, Sept. 26, Prince William, Prince George and the rest of the Cambridge family welcomed naturalist Sir David Attenborough to their Kensington Palace home for a special screening of the documentary ahead of its airing on television. The 94-year-old environmentalist is a personal favorite of the young royal, who received a giant shark tooth from Attenborough.

Prince George is a budding environmentalist like his father and his forefathers. During the lockdown in April, Kate Middleton revealed in a video chat with school kids that her eldest child has been watching a lot of Attenborough's nature documentaries in isolation. 

But, Attenborough's gift to the young prince sparked a controversy. According to InStyle, the Culture minister in Malta, Jose Herrera, wants Prince George to return the artifact since the shark tooth is part of the Maltese natural heritage.

Apparently, Attenborough told Prince George that he found the shark tooth while spending a vacation in the coast of Malta in the 1960s. The natural artifact is estimated to be over 23 million years old and Herrera said he is making steps to retrieve the shark tooth from the royal family.