Sir David Attenborough gave Prince George a special fossil during a private viewing of his new documentary.
The 94-year-old broadcaster joined the Duke and Duchess of Cambridge and their three children - Prince George, seven, Princess Charlotte, five, and Prince Louis, two - at Kensington Palace to watch 'A Life On Our Planet', and Attenborough took the opportunity to give a fossilised giant tooth from an extinct shark to the young royal.
Prince George was fascinated by the fossil, which came from a carcharocles megalodon, a shark that was once a sea predator.
Attenborough found the fossil during a family holiday to Malta in the late 1960s.
The broadcaster - who was previously interviewed by Prince William at the World Economic Forum in Davos, Switzerland, in 2019 - also spent time chatting to the royals after watching his new documentary.
Meanwhile, Prince William has admitted he has a "new sense of purpose" in protecting the planet now he has children.
The 38-year-old royal has "always loved nature" but his family has given him added drive to do what he can to look after the natural world for future generations.
Speaking in the upcoming ITV documentary 'Prince William: A Planet For Us All', he said: "Now I have got George, Charlotte and now Louis in my life - your outlook does change. You want to hand over to the next generation, the wildlife in a much better condition.
"I always believe it is possible to give young people hope and belief that things can get fixed.
"I have the belief that if we all work together, we can make a difference."