Prince William told this hilarious knock knock joke while meeting school pupils in the West Midlands. It's Princess Charlotte's favourite joke, but did it make you laugh? Follow us for more royal news, history, and highlights: ♛ Subscribe to our YouTube channel (tap the bell icon and stay up to date with all the latest Royal videos!) - https://bit.ly/3jNBYZ7 ♛ Find us on TikTok https://www.tiktok.com/@royalfamilychannel ♛ Follow us on Facebook - https://www.facebook.com/RoyalFamilyChannel ♛ Tweet with us! - https://twitter.com/RoyalFamilyITNP