The Duke of Cambridge's tribute accompanied a sweet photo of Prince Philip and Prince George - captured by Kate Middleton herself - shared to the Kensington Royal Instagram page.
It read: "My grandfather's century of life was defined by service - to his country and Commonwealth, to his wife and Queen, and to our family."
Fans couldn't help but notice the emphasis on a life of service, suggesting it was a subtle dig at Harry's decision to leave his duty behind and jet off to California.
Prince William continued: "I feel lucky to have not just had his example to guide me, but his enduring presence well into my own adult life – both through good times and the hardest days."
He went on to emphasise how glad he was that his wife, Kate Middleton, had a chance to get to know Prince Philip and fondly recognised the special memories his children made with their great grandpa. The royal also gave a special mention to Philip's "mischievous" sense of humour.
As one final sucker punch to his younger brother, William ended the statement with: "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."
Fans were quick to wave their Team Cambridge flags in the comments, voicing their support for the heir to the throne.
"What a beautiful and respectful statement," one user penned
"Moving works from our future King and what a King you'll be. Prince Philip would be proud." another added.
"Beautiful tribute to your Grandfather. You're a wonderful grandson & asset to the Monarchy." a third chimed in.
Prince Philip passed away on Friday, 9th April, 2021.
The sad news was broken via a statement from the Palace, which read: "It is with deep sorrow that Her Majesty The Queen has announced 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."
A few members of the Firm have since gathered for a small service to honour the consort. Among the attendees was the controversial Prince Andrew who revealed how the Queen is coping through this troubling time.
"I feel very sorry and supportive of my mother who's feeling it probably more than everybody else." the Duke told the BBC. "The Queen, as you would expect, is an incredibly stoic person and she described his passing as a miracle."
He went on the explain that Her Majesty revealed that losing the great love of her life has "left a huge void in her heart".
The funeral is to be held on Saturday, April 17th at 3 PM UK time (12 AM midnight in Australia). It is to be broadcast on Channel 9 and on the ABC.