The Prince of Wales and the Duchess of Cornwall were among the royals to send birthday wishes to the Duke and Duchess of Cambridge's youngest child, Prince Louis, on Friday.
Clarence House reposted the sweet photo that the Cambridges had shared on their social media accounts, which showed Louis on his way to his first day of nursery at Willcocks Nursery School.
READ: Pregnant Meghan Markle carried Archie over her baby bump in new photos
The caption, which was accompanied by a cake emoji, read: "A very Happy Birthday to Prince Louis, who turns three today."
WATCH: Unseen photos of George, Charlotte and Louis revealed
Charles has a special bond with his grandson and royal fans have been treated to some touching images of the pair over the last three years. On Louis' second birthday last year, Clarence House shared a black and white snapshot of Charles and the little royal sharing a hug.
© Photo: TwitterCharles and Camilla's account marked Prince Louis' birthday
Louis also stole the show in photos released to mark Prince Charles' 70th birthday in 2018. In one family portrait, which also included the Duke and Duchess of Sussex, the royals were captured laughing as Louis, who was four months old at the time, affectionately grabbed his grandfather's face.
And in more heartwarming shots, Charles held Louis' hands as the tot sat in his mother Kate's arms, while another showed the future King proudly holding his baby grandson.
MORE: Prince Louis' first official portrait with the Queen and Prince Philip revealed
MORE: Prince George and Princess Charlotte's photo with the Queen makes history - here's why
The full photo that the Cambridges shared
Back in 2019, a hilarious moment between Camilla and Louis was caught on camera at Trooping the Colour. The little Prince nearly knocked off his step-grandmother's hat from waving so hard at the fly-past, making Camilla laugh in the process.
Prince Louis was born at the Lindo Wing of St Mary's Hospital in Paddington on 23 April 2018.
The tot's full name was announced as Prince Louis Arthur Charles just a few days after his birth, and he is fifth in line to the throne behind sister Charlotte.
As well as Prince George, Princess Charlotte and Prince Louis, Prince Charles is also grandfather to Prince Harry and Meghan's son, Archie.
Charles will become a grandfather for the fifth time when the Duchess of Sussex gives birth to a baby girl this summer.
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