“We’re talking about your birthday,” Charles told his father.
“Well, I’ve got to be alive for it, haven’t I?” the late Duke responded. "I knew you'd say that!" Charles said.
The following day, Philip died at 99 years old.
“It is with deep sorrow that Her Majesty The Queen has announced the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh,” Buckingham Palace announced on Twitter at the time.
Other family members spoke, including Prince Harry, who praised Queen Elizabeth and Prince Philip's long-lasting marriage.
“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,” he shared. “What you see is what you got with my grandfather. He was unapologetically him."
“He’s always been a huge presence behind everything we’ve done, really,” Prince William said.
Meanwhile, Zara Tindall said Philip "was getting older and he absolutely hated it."
“He was the worst patient in the world! But, actually, you never really prepare yourself for losing him because he was always there," she added.
“The documentary-makers have been inside Buckingham Palace to meet the Duke’s long-serving staff and to capture his study, private office and library, exactly as they were during his seven decades at the heart of royal life,” the BBC said in a press release about the flick, which will premiere in the U.K. on BBC One Wednesday, September 22, at 9 p.m.
“With special access to the Queen’s private cine-film collection, this film is an unrivaled portrait of a man with a unique place in royal history — by those who knew him best,” the message continued.