Prince Louis of Cambridge is about to celebrate his first birthday.

The Duke and Duchess of Cambridge’s third and youngest child reaches his  milestone on Tuesday.

Prince Louis Arthur Charles arrived at 11.01am, weighing 8lb 7oz, on April 23 2018 – patriotic St George’s Day.

He is fifth in line to the throne, a great-grandchild of the Queen and the Duke of Edinburgh and a younger sibling of Prince George and Princess Charlotte.

Louis made his debut in Kate’s arms as his proud parents showed him off to the world on the steps of the Lindo Wing of St Mary’s Hospital in Paddington, London, just hours after he was born.

The name Louis was already one of George’s middle names and pays tribute to the Prince of Wales’s great-uncle, Earl Mountbatten, who was murdered by the IRA.

Prince Louis in his car seat as he is taken home to Kensington Palace from hospital Credit: Dominic Lipinski/PA

William and Kate released photos of their son soon after – including one of him being cuddled by his big sister Charlotte on her third birthday when Louis was only about a week old.

Louis was sleeping soundly, as Charlotte put a protective arm around her baby brother and planted a kiss on his forehead.

The prince was next seen fast asleep at his christening in July, and alert and smiling in family photographs released to mark the occasion.

Kate with Louis at his christening Credit: Dominic Lipinski/PA

Louis, who appears to have inherited the brown Middleton eyes from Kate’s side of the family, was pictured with his wider family, including the Duke and Duchess of Sussex and the Prince of Wales and the Duchess of Cornwall in photos released to mark Charles’s 70th birthday in November.

Later the same month, Kate revealed as she met the public during a visit to Leicester University: “Louis’ getting bigger. I can’t believe he’s seven months now.

“He’s getting a big boy.”

Sporting a grin, the prince was last pictured about four months ago when he was surrounded by his siblings and parents in the grounds of Anmer Hall in Norfolk for the family’s official Christmas card.

In March, Kate revealed on a visit to a children’s centre that Louis, then about 11 months old, was “bombing around” on a walker.

“He just wants to pull himself up all the time. He’s got these little walkers and is bombing around on them,” she told a fellow parent.