The sentiments may have been similar – but the styles could not have been more contrasting.
In days gone by, the royal brothers would have put out a joint statement commemorating such an important role model in both their lives. Yet with tensions between the two princes seemingly still bristling ahead of Prince Philip's funeral on Saturday, we were left to decipher the coded messages contained within.
William's 173-word missive was the first to drop on the Kensington Palace website at 2pm, paying tribute to "a century of life defined by service".
Praising his grandfather as an "extraordinary man and part of an extraordinary generation", the seemly eulogy gave a nod to the Duke of Edinburgh's "infectious sense of adventure as well as his mischievous sense of humour".
There was also acknowledgement of his "enduring presence... both through good times and the hardest days", a reference to his stalwart support following the death of Diana, Princess of Wales, when he encouraged William to walk behind their mother’s coffin with the words: "If I walk, will you walk with me?"
Yet it was the final, somewhat pointed, paragraph which took royal-watchers by surprise as William said: "Catherine and I will continue to do what he would have wanted and will support the Queen in the years ahead. I will miss my Grandpa, but I know he would want us to get on with the job."
The carefully-chosen words were inevitably interpreted by some as a bold attempt to contrast the Cambridges' own dutiful behaviour with the Sussexes' departure from royal duty.
While William was undoubtedly intending to reflect his grandfather's no-nonsense approach to life, there is no escaping the inherent implication that he and his wife are the embodiment of the Duke and the Queen's "keep calm and carry on mantra" compared to their escapee brother and sister-in-law.
During the Sussexes' interview with Oprah Winfrey, Harry suggested his brother and father Prince Charles were "trapped" in the monarchy. This was William's way of responding to that extraordinary two-hour tell-all on his own terms, stating the case for personal sacrifice in the face of public duty.
The inclusion of the final paragraph is all the more intriguing since The Telegraph understands it was not included in the statement when it was first drafted over the weekend.
It had been originally mooted that William's tribute might go out alongside his father's on Saturday, before it was decided that all of Philip's children should pay tribute before his grandchildren.
Although the palace was made aware of the timing of Harry's statement, royal aides were not involved in the wording before it was circulated by the Sussexes' global press secretary at 2.30pm.
You did not need to look far to find similar hidden meaning in the much more informal 197-word homage to "my grandpa: master of the barbecue, legend of banter and cheeky right 'til the end".
Having been accused in the past of issuing Americanised statements bearing the hallmarks of Meghan's red pen, the upbeat paean could not have been more unquestionably Harry if had donned a ginger wig as he reflected that, if he was here right now, his grandfather "would say to all of us, beer in hand: 'Oh, do get on with it!'"
Like his brother, the Montecito-based prince could not resist a reference to his own immediate family in absentia, revealing: "Meghan, Archie, and I (as well as your future great-granddaughter) will always hold a special place for you in our hearts." The pregnant Duchess has not flown over for the funeral on doctors' advice.
Yet his attempt to draw a personal parallel with the so-called Duke of Hazard was plain to see as he described his grandfather as someone who was "authentically himself", who "could hold the attention of any room due to his charm – and also because you never knew what he might say next".
Harry's decision to sign off with the Royal Marines' motto "Per Mare, Per Terram" ("By Sea, By Land") also appeared a thinly-veiled reference to his superior military service to William, along with a reminder that he had inherited the role of Captain General of the regiment from his grandfather – only to be stripped of such honorary appointments post-"Megxit", seemingly against his will.
Having made no secret of the fact that he was disappointed not to be able to maintain his military ties, the inclusion of the four-word Latin phrase appeared designed to tell the world that while he may no longer be a working royal, like his grandfather he will forever remain one who saw active service.
It may have also been an echo of Harry's new-found Californian way of life as it is a military custom in much of the US armed forces to sign off letters, speeches and even individual social interactions with a unit motto. Members of the US Marine Corps, for example, end correspondence with the words "semper fi" (short for Semper Fidelis, Latin for "always faithful").
But the custom is not practised in the British Armed Forces, perhaps saying more about the direction of Harry's future career than his previous one.
As they prepare to be reunited for the first time in more than a year behind their beloved Grandpa's coffin, there remains no mistaking the divergence between two brothers on very different paths.
It remains to be seen whether the death of the Royal family's former patriarch will help William and Harry to bury their differences along with the man who encouraged them to forever be brothers in arms.