Prince William made a surprise appearance on Dancing with the Stars on Tuesday night to show his support for contestant Robert Irwin. The Prince of Wales, 43, popped in unexpectedly during the 20th anniversary episode of the competition dance show to share a few words of encouragement with Irwin, an Earthshot Prize ambassador for William's environmental initiative, which aims to find innovative solutions to repair and protect the planet.Irwin, 21, told his dancing partner Witney Carson that he was supposed to be in Brazil for the Earthshot Prize awards in Rio de Janeiro on Nov.