The video, shared to the Duke and Duchess of Cambridge's official Instagram, shows Prince Louis, Princess Charlotte and Prince George asking veteran broadcaster and natural historian Sir David Attenborough questions about the environment.
It's believed to be the first time the children have spoken together on camera.
"We've got some questions for you, @DavidAttenborough," the post says.
In the video, Prince George asks Attenborough which animal he thinks will next become extinct.
