New Delhi, Sept. 17 -- The Duke and Duchess of Sussex, Prince Harry and Meghan Markle, are set to make a surprise appearance in a new ABC News special marking the 70th anniversary of Disneyland.

The documentary, titled 'The Happiest Story on Earth: 70 Years of Disneyland - Special Edition of 20/20', will air on September 21 in the US, and features a lineup of celebrities sharing personal memories from the theme park.

ABC confirmed the royal couple's involvement in a press release, "Viewers will hear reflections on childhood visits to the park from some of Disney's biggest fans. And an exclusive message from Prince Harry and Meghan, Duchess of Sussex, on what the park means to them and their family."

The Sussexes recently visited Disney...