Prince Charles reveals last words to Prince Philip on eve of his death, in BBC doco tribute

Prince Philip, Duke of Edinburgh and Prince Charles, Prince of Wales attend the unveiling of a statue of Queen Elizabeth The Queen Mother. Photo / Getty Images

Prince Charles has revealed his final words to his dad, the late Prince Philip, during a conversation the two had the day before he died.

In a new documentary, Prince Charles recalls how he talked to his father about the plans to celebrate his 100th birthday.

On April 8, Prince Charles called his father, the late Duke of Edinburgh, to ask about the party to celebrate his 100th birthday in June.

"We're talking about your birthday," he recalled telling his dad more than once, as the duke had failed to hear him.

"And whether there's going to be a reception."

Prince Philip's reply showed that, despite his ill health, he was still in his usual good spirits: "Well, I've got to be alive for it, haven't I?"

"I knew you'd say that," Charles replied.

The celebration was not to happen, as the Duke of Edinburgh died aged 99, on April 9.

Prince Charles, Prince of Wales follows Prince Philip, Duke of Edinburgh's coffin. Photo / Getty Images

The conversation between the two was discussed during a BBC documentary that will air in the UK next week.

The documentary also features Prince Harry, speaking from his home in California.

Harry says his grandfather was "unapologetically him" and praised his unwavering support for the Queen.

"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," Harry said.

Prince Philip's granddaughter Zara Tindall says the duke "absolutely hated" getting older.

"He was the worst patient in the world! But, actually, you never really prepare yourself for losing him because he was always there," she said.

• "Prince Philip: The Royal Family Remembers" is set to appear in the UK on BBC One and features other senior royals paying tribute to the late duke.