New documentary reveals Prince Charles' last conversation with Prince Philip

An upcoming documentary reveals snippets of the conversation Prince Charles had with his late father Prince Philip.

According to People magazine, the documentary titled, 'Prince Philip: The Royal Family Remembers', by BBC One about the legacy left by Queen Elizabeth's husband of 73 years, Prince Charles reportedly reveals he spoke on the phone with the Prince of Edinburgh one day prior to his death.

Philip died at the age of 99 on April 9, nearly two months shy of his 100th birthday. A news outlet reported that Charles and Philip were discussing how to celebrate the big milestone in what is believed to be their final conversation.

"We're talking about your birthday," Charles said to his father in a phone call on April 8, according to the outlet. Charles allegedly repeated again, "We're talking about your birthday! And whether there's going to be reception!"

Philip, who was at his home in Windsor following a hospitalization, cracked, "Well, I've got to be alive for it, haven't I?" Replying Charles said, "I knew you'd say that!"

BBC announced earlier this month that the upcoming documentary "Prince Philip: The Royal Family Remembers" will feature all four of Prince Philip and the queen's children: Charles, Princess Anne, Prince Andrew and Prince Edward. The project was originally produced to mark Philip's 100th birthday on June 10.

"There are poignant recollections, plenty of humour and numerous fresh insights into the character and legacy of this royal pioneer. With special access to the Queen's private cine-film collection, this film is an unrivalled portrait of a man with a unique place in royal history - by those who knew him best," the BBC said in a statement, as per Fox News.

Prince Charles had offered a heartfelt tribute to his father in April following his death.

Philip was hospitalized months before his death. On February 16, the prince was admitted to a London hospital after feeling unwell.

On March 3, he underwent a procedure for a pre-existing heart condition at St Bartholomew's Hospital before being transferred back to King Edward VII hospital on March 5 and ultimately released home on March 16.

Philip married then-Princess Elizabeth in 1947 and is the longest-serving royal consort in British history.