Devastating on-camera appearances have been part and parcel of palace life for decades now. Prince Charles started this dubious trend in 1994 when he admitted to Jonathan Dimbleby he had cheated on wife Diana, Princess of Wales, who infamously followed in his bespoke-shod stead the following year with her "three of us in the marriage" BBC outpouring.
In March, it was their son Prince Harry's turn – although really he was the second-string act to wife Meghan, the Duchess of Sussex's scene-stealing turn.
However, now Prince William has joined their number having released a deeply emotional and devastating video addressing the findings of the BBC inquiry into his mother's Panorama appearance.
Overnight, the findings of an inquiry conducted by Lord Dyson into the Panorama interview were released, finding that journalist Martin Bashir had used "deceitful behaviour" to get the Princess to agree to the extraordinary sit-down interview. (Bashir used a graphic designer to unwittingly mock up fake bank statements which purported to prove to Diana's brother, Earl Spencer, and later Diana herself, that people close to the royal were being paid by the security services and the media.)
While Prince Harry put out a statement movingly describing her as an "incredible woman" who "was resilient, brave and unquestionably honest", William has just blown the world's socks off.
Reading from papers in his hand, the chosen backdrop some nondescript palace exterior, barely contained emotion rippling below the surface, the 38-year-old delivered a searing, historic statement to camera saying that her Panorama interview "was a major contribution to making my parents' relationship worse and has since hurt countless others".
He said: "The BBC's failures contributed significantly to her fear, paranoia and isolation that I remember from those final years with her."
He also said that Diana had been "failed" by the national broadcaster.
"These failings … not only let my mother down, and my family down; they let the public down too."
Make no mistake here: The world just watched William step up and assume total moral and public leadership of the royal family from a public perspective.
And Harry? Oh poor Harry has been left trailing in his wake.
The fact that William chose to do a video is remarkable. While he has delivered statements supporting his various causes straight down the barrel, this is the first time that any member of the royal house has delivered a reaction of this nature to camera. (The Queen's televised addresses notwithstanding nor Charles' recent touching statement after the death of his father, Prince Philip.)
Another marked departure from the royal playbooks is the simmering emotion on clear show here. What stiff upper lip?
While Harry and Meghan have cast the royal family as a clutch of essentially cold fish, William has just gone a way to make that characterisation seem a tad redundant.
In choosing to go down this route, rather than only putting out a strongly worded written missive, William was sending a clear message: That he has no intention of hewing to the status quo and will act how he thinks best. (This calls to mind the fact he was the only member of the house of Windsor to address the Sussexes' racism claims when asked directly by the press, offering up a forceful "We're very much not a racist family.")
One of the most conspicuous differences between William and Harry's reactions lies in their respective language choices. The elder Wales prince used "my mother," "my view" and "I" while the younger's crucially deployed "our mother". Those two words from William – "I" and "my" – are so telling.
Not once in his piece to camera does William mention Harry, even in the most oblique terms. There is no equivocation here: The Duke of Cambridge has just effectively excised his younger, wayward sibling from the narrative.
Given the consideration and time that goes into every single detail (heck, the choice of William's insipid blazer for the video probably involved several brow-furrowing, lengthy meetings) this very conscious expunging of Harry was no oversight.
If there was any doubt over who has just been "crowned", by Fleet Street anyway, in the Cambridge vs Sussex fracas then look no further. A winner has been anointed with William and his powerful video dominating at least three of Friday's frontages in the UK with Harry essentially ignored in the maelstrom.
The word that comes to mind today is "irrelevance". Harry left the UK to escape his elder brother's shadow, to strike out on his own. However, the irony here is that in that quest to define himself and forge his own independent identity, he seems to have given William the breathing room to assert himself in a completely new – and let's be honest, thrilling – way.
Despite both men putting out statements as loving, devoted sons who lost a cherished mother, Harry's words have somehow ended up as only a footnote to William's outpouring.
What is also noteworthy here is the paradigm shift around Diana's memory.
For months now, starting with the Sussexes' Oprah TV interview back in March, Harry has repeatedly cited and called to the fore his mother's life and legacy and has thus unintentionally come to "own" her public memory.
That unintended monopolisation is now over.
William has reminded the world that the Princess of Wales had two sons – two boys lost their mother that day, not just the man who never seems to miss an opportunity to discuss his loss.
The fact that this is all happening the day before Harry's mental health TV series, The Me You Can't See, which includes footage of Harry at his mother's funeral, makes this rejoinder ever more cutting.
In years to come, there is every chance that commentators and biographers will look back and point to William's video today as a decisive moment in his journey to the throne. Not only has he stood up for his mother's memory but he has unequivocally demonstrated he will act, speak – and one day, rule – exactly how he wants.
Things are about to get much more interesting.
Daniela Elser is a royal expert and a writer with more than 15 years' experience working with a number of Australia's leading media titles.