The Prince and Princess of Wales's son Prince Louis penned a heartfelt message as he stepped out for his mother's Christmas carol service on Friday.
The six-year-old placed a message on the Kindness Tree outside Westminster Abbey, which featured dedications personally written from guests to people who have shown love, empathy and kindness.
The handwritten note on the red label was dedicated to Kate's parents, Carole and Michael Middleton, with Louis writing: "Thank you to granny and grandpa because they have played games with me."
The Middletons were among the 1,600 congregation, along with Kate's younger siblings, Pippa Matthews and James Middleton.
George, Charlotte and Louis share a close bond with their maternal grandparents, who live just half hour away from the Waleses in Windsor at their mansion in Bucklebury.
© GettyCarole, 69, and Michael, 75, have supported their daughter and her family throughout a difficult year as Kate underwent major abdominal surgery in January and cancer treatment.
© GettyThe Middletons featured in the moving video message that the Princess shared to confirm the end of her chemotherapy in September.
Carole and Michael were spotted playing a card game with William, Kate, George, Charlotte and Louis inside Anmer Hall in Norfolk.
© Kensington PalaceLouis was pictured sitting on his father William's lap next to his grandfather, Michael, as Carole and George both looked intently looked at their cards.
Earlier this year, the Middletons joined William at Royal Ascot in June, with the Prince demonstrating an act of chivalry as he helped to free his mother-in-law when her heel got stuck in the grass.
© Kensington PalaceWilliam first met Kate's family when their friendship turned to romance at university
The Princess' brother, James, recalls giving William a bit of a tough time when he first began dating his sister.
Writing in his debut book, Meet Ella: The Dog Who Saved My Life, James said: "By now, William has been dating Catherine for six years, so I know him well and there is no scramble to clear up when he comes to supper. But I remember putting him through his paces when we first met. Did he deserve my sister? He had to earn my trust."
He later added that William quickly bonded with the Middletons, writing: "I saw a lot of William when he was an officer cadet at Sandhurst, which is fairly close to Bucklebury. So by the time I'm toing and froing between Edinburgh and London, he's become part of the family."
