Prince Philip died on April 9, the same day Prince Charles and wife Camilla celebrated their 16th wedding anniversary.
The bittersweet coincidence means both occasions will now be forever linked, a fact that is bound to cause the heir to the throne added sadness.
Charles and Camilla, the Duchess of Cornwall, tied the knot on April 9, 2005, almost 35 years after they first met.
The couple met in the 1970s and famously had an affair in the 1980s, when they were both still married.
They officially dated for six years before their wedding in 2005, when they exchanged vows in a civil ceremony at Windsor Guildhall.
Queen Elizabeth and Prince Philip did not attend the civil wedding ceremony, but they were present at the Service of Prayer and Dedication at St George's Chapel.
Prince Philip died on Friday evening (NZ time), aged 99.
He passed away peacefully at home, with the Queen at his bedside.
The Duke of Edinburgh's death at Windsor Castle was announced late Friday night (NZT) and has put Britain, and much of the Commonwealth, into a period of mourning ahead of his funeral next weekend.
The Daily Telegraph has reported the Duke wished to pass away "in his own bed" and on "his own terms".
"He spent most of the four weeks he was in hospital trying to get home. They operated on his heart in a bid to give him a little longer, maybe with the 100th birthday in mind," a source told the Daily Telegraph.
"There is no way he would have wanted to die in hospital," the source added.
The Queen has previously described Philip as her "strength and stay".
Buckingham Palace said in a statement late Friday night (NZT): "It is with deep sorrow that Her Majesty The Queen announces the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh.
"His Royal Highness passed away peacefully this morning at Windsor Castle."
The new doco follows the Sussexes' Harry & Meghan, Live to Lead, and Heart of Invictus.