The Duke and Duchess of Cambridge will attend the screening of David Attenborough's Natural History Museum Alive 3D on 11 December.
The couple will meet Sir David Attenborough and other attendees before watching the film which is due to be broadcast on Sky next year.
The ground-breaking film sees David Attenborough bringing to life his favourite extinct creatures through 3D technology. New mum Kate became Patron of the London museum in April.
Kensington Palace also announced on Wednesday that William will attend the British Military Tournament, at Earls Court Exhibition Centre, London, on 8 December.
The event will raise funds for the three national charities of the National Armed Forces: ABF The Soldiers’ Charity, The Royal Navy & Royal Marines Charity and The Royal Air Force Benevolent Fund.