VIDEO: Princess Charlotte's cutest moments
According to The Times, David said that meeting the young royals was "charming," adding "it was a very nice domestic occasion". The 94-year-old gave George a fossil tooth from a giant shark, which proved to be a hit.
Princess Charlotte was especially excited to see David Attenborough
"When I was his age, I remember being given fossils by a grown-up, so I thought I would do the same," he said.
"[George asked] What it was? How big it was? And so on. He was certainly very interested. He seemed to like it. He is very interested in fossils. She [Charlotte] was too. All three seemed charming."
George, Charlotte and Louis are all fans of David, so much so that they are believed to have asked their parents to meet him.
Prince George was very interested in his gift from David
A photo of the trio meeting David was released by Kensington Palace on Saturday evening, showing Charlotte looking particularly excited with her hands held up to her face in surprise.
Later in the evening, David joined William for a private outdoor screening of his film, David Attenborough: A Life on our Planet, which is showing in cinemas from 28 September and on Netflix from 4 October.
David and William have joined forces regularly in the past, most recently in January, when Sir David narrated the announcement of the Earthshot Prize.
Charlotte and George met David after school on Thursday
The multi-million pound initiative aims to find 50 solutions to our greatest environmental problems over the next decade and Kensington Palace is set to announce more details in the coming days.
William and Kate are also seen chatting to Sir David in a new ITV documentary which airs on October 5, with the Duchess saying of her children: "They’re massive fans."
In Prince William: A Planet for Us All, the Duke says becoming a father has spurred him on to do more to save the planet. "I have always loved nature, but fatherhood has given me a new sense of purpose,” he says.
“Now I’ve got George, Charlotte and Louis in my life, your outlook does change. You want to hand over to the next generation, the wildlife, in a much better condition."
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