Prince William, Queen Elizabeth, Prince Harry and Prince Philip.Photo: Getty

The intimate tribute film that features more than a dozen members of the royal family paying tribute toPrince Philipmakes its debut in America next month.
In PEOPLE’s exclusive new trailer for the documentary, William and Harry’s cousinPrincess Beatricereadies herself to speak about her beloved grandfather while William goofs around with the clapboard, laughing about what “I’ve signed myself up for.”
William, 39, says his grandfather was “the heart of the family” and has “always been a huge presence behind everything we’ve done, really.”
Meanwhile, 37-year-old Harry discusses Philip’s forthright character: “What you see is what you got with my grandfather. The authenticness of him. He was unapologetically him.”
Charles’s wife,Camilla, Duchess of Cornwallmarvels at Philip’s astonishing life, saying, “I just asked him about his childhood. It was absolutely riveting.”
First airing in the U.K. in September, the documentary also sees Charles, 73, say of his father, ‘We were lucky to have him for nearly 100 years."
Queen and Duke of Edinburgh on Their 73rd Wedding Anniversary.Chris Jackson/Getty Images

Billed as a look at the “man behind the crown,” it features Philip’s former staffers and royal family talking about his life and legacy.
Originally conceived to markPrince Philip’s 100th birthday and showcasingclips from the Queen’s private film collection, the documentary features interviews that were completed both before and after his death. It also goes inside Buckingham Palace into the Duke of Edinburgh’s study, private office and library.
Queen Elizabeth and Prince Philip.Steve Parsons/PA Images via Getty

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Philip died on April 9, just two months before what would have been his100th birthday, and the family gathered for his funeral on April 17 at St. George’s Chapel in Windsor Castle.
It would have been Philip and the Queen’s 74th wedding anniversary on Saturday. Two of his granddaughtersPrincess EugenieandZara Tindall, along with their families, paid a subtle but poignant tribute on Sunday. Their sonsAugust Brooksbankand Lucas Tindall — both of whom have Philip as a middle name —were baptizedin the presence of the Queen, 95, and other members of the royal family at the Royal Chapel of All Saints in Windsor Great Park.
Prince Philip: The Royal Family Rememberslaunches exclusively on discovery+ on December 16.
source: people.com