Prince Harry and Prince Charles Reminisce on Prince Philip's Grandfatherly Advice and Sharp Wit

Max Mumby/Indigo/Getty Prince Philip and Prince Harry

Prince Philip was known for his way with words, and Prince Charles and Prince Harry are sharing some of their most unforgettable exchanges with the Duke of Edinburgh in an upcoming documentary on his nearly 100-year life.

In Prince Philip: The Royal Family Remembers, airing Wednesday night in the U.K. on BBC One, Charles reveals what may have been the last conversation he had with his father.

Last spring when Charles, 72, brought up Philip's upcoming birthday (the Duke would have turned 100 on June 10, but he died on April 9), Philip didn't miss a beat: "Well, I've got to be alive for it, haven't I?" P

Charles replied as only a son can: "I knew you'd say that!"

Mark Cuthbert/UK Press via Getty Images Prince Philip and Prince Charles

Philip "absolutely hated" getting older and "was the worst patient in the world!" shares granddaughter Zara Tindall, according to the Daily Mail.

She adds, "But, actually, you never really prepare yourself for losing him because he was always there."

Camilla, Duchess of Cornwall notes that her father-in-law's death "felt like the end of an era. They're a very difficult generation to live up to but I'm very proud and very pleased that I knew him."

BBC A still from the Queen's video collection showing Philip and Charles and Anne playing

The documentary provides an "unrivaled" glimpse into Philip's life, with never-before-seen home movies from Queen Elizabeth's private collection, as well as interviews from 15 of his children and grandchildren, including Prince William, Princess Anne, Princess Eugenie and Harry (Kate Middleton, Meghan Markle, the Cambridge children and the Queen herself did not sit for interviews).

Looking farther back, the documentary also shares an exchange Philip and Harry shared that was characteristically poignent yet to-the-point.

Before the young prince was sent on his first tour of Afghanistan in 2012 as part of his service in the Royal Air Force, Philip "was very matter of fact and just said, 'Make sure you come back alive,'" Harry shares, per ITV.

EDDIE MULHOLLAND/POOL/AFP via Getty Prince Harry and Prince Philip

When Harry, now 37, returned the next year, "there wasn't a deep level of discussion, more a case of, 'Well you made it. How was it?' That's how he was."

Adds Harry, "He was very much a listener, he sort of set the scene for you to be able to share as much as you wanted to share but he would never probe."

As a naval veteran himself, not to mention the father and grandfather of many service members, Philip's respect for the military was always clear.

"He's always set a very good example about how we have to look after the welfare of the military and represent them and be there for them," says William, 39, because Philip understood "the trials and tribulations that they all go through."

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Chris Young/AP/Shutterstock Prince Philip and Queen Elizabeth

Prince Philip: The Royal Family Remembers will share more memories of the Duke of Edinburgh, from his love of barbecuing to his 73-year marriage to the Queen.

Says Harry, "From my grandmother's perspective, to have someone like that on your shoulder for 73 years of marriage — it doesn't get better than that."