Prince William and Kate welcomed the legendary naturalist to Kensington Palace last week, where Prince George, seven, Princess Charlotte, five, and two-year-old Prince Louis got to meet him in the garden after school.
Sir David, 94, was at the Palace to watch his new film, A Life on our Planet, with the Duke, but did you notice the hilarious mistake in the photo of the pair taken by the Duchess?
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Instead of attending a film premiere for the feature-length documentary, the two men sat together in the garden at Kensington Palace, both under blankets to protect them from the chilly autumn weather.
Aides had set out two director's chairs with their names on, but the Duke and Sir David amusingly decided to sit in the wrong ones!
Their seat swap provoked brilliant reactions from royal fans, with one writing on Twitter: "I love the fact they are sitting in each other's chair," while another said: "Adorable that they've switched their director’s chairs!"
The pair sat in one another's chairs during the screening
During his afternoon at the palace, Sir David gave Prince George a fossilised giant shark's tooth. The memento was found by Sir David during a family holiday to Malta in the late 1960s. It was embedded in the island#s soft yellow limestone, which was laid down during the Miocene period some 23 million years ago.
In another photograph, George is seen excitedly examining the tooth, as his little brother Louis, sitting alongside their father, looks on.
A source told HELLO!: "It was very sweet, all three children were playing with it."
Sir David gave Prince George a fossilised giant shark's tooth
In a trailer for a new ITV documentary, Prince William: A Planet For Us All, which will be aired next month, footage shows the Duke and Duchess of Cambridge meeting Sir David in Birkenhead last year.
Kate can be heard telling the natural historian: "The children were very upset that we were coming to see you and they weren't coming. They're massive fans of yours."
David Attenborough: A Life On Our Planet, produced by WWF and Silverback Films, premieres in cinemas on Monday and will launch on Netflix on 4 October.
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