Prince Harry will reunite with the royal family for a documentary about Prince Philip

• Prince Harry will join Prince William and other royals in paying tribute to Prince Philip.
• The royals will appear in a documentary about Philip's life, which airs on the BBC on September 22.
• Philip died on April 9 at the age of 99.

The Duke of Sussex is set to take part in his first royal family project since quitting official duties last year.

Prince Harry will appear alongside other royals, including Prince William and Prince Charles, in a BBC documentary about the late Prince Philip.

The program, which will air on September 22, was originally commissioned to celebrate Philip's 100th birthday in June of this year. It has been repurposed as a tribute film following his death on April 9, according to a BBC press release.

"For the first time on television, more than a dozen members of the Royal family offer their personal thoughts and reflections as they pay an historic tribute to the extraordinary life of His Royal Highness Prince Philip Duke of Edinburgh," the press release reads.

"All the children of the Queen and the Duke, along with their adult grandchildren and other members of the Royal family have agreed to take part in this unique portrait of the longest-serving consort in royal history," it added.

More than a dozen royals, including Philip's children, Princess Anne and Prince Edward, and his grandchildren, Princess Beatrice, Princess Eugenie, Peter Phillips, Zara Tindall, and Lady Louise Windsor, are confirmed to appear in the project, according to The Telegraph.

Prince Andrew will also appear in the documentary, a spokesperson for the BBC told Insider.

The Duke of Edinburgh died on April 9 at the age of 99 after previously being hospitalized for four weeks earlier this year, in what the palace initially described as a precautionary measure for a preexisting condition.

Harry flew from California to attend the funeral at St George's Chapel in Windsor on April 17. However, Markle, who was pregnant at the time, did not receive medical clearance to fly and watched the ceremony on TV, her spokesperson previously told Insider.

Markle and Kate Middleton will not appear in the documentary. A spokesperson for the BBC told Insider that "no spouses of the grandchildren are interviewed" for the project.

Representatives for the Duke and Duchess of Sussex did not immediately respond to Insider's request for comment.