Prince Louis holding his mother Kate Middleton\'s hand at the London Palladium in Dec 2020.

Prince Louis holding his mother Kate Middleton's hand at the London Palladium in Dec 2020.Getty

Today the Duke and Duchess of Cambridge, Prince William and Kate Middleton's third and youngest child Louis Arthur Charles celebrates his third birthday. Here's everything you need to know. 

Prince Louis of Cambridge was born on April 23, 2018. Little brother of Prince George and Princess Charlotte, Prince Louis is fifth in line to the throne. 

On the day after Louis's birth, April 24 2018 gun salutes rang out from the Tower of London and Hyde Park and bell ringings at Westminster Abbey marked the birth. His birth was officially announced on April 17, 2018. He was named Louis Arthur Charles, with the first and last names honouring his paternal great-great-great-uncle Louis Mountbatten, 1st Earl Mountbatten of Burma, and his last name for his paternal grandfather Charles, Prince of Wales, respectively.

Prince Louis was christened on July 9, 2018, by the Archbishop of Canterbury in the Chapel Royal at St. James's Palace, using water from the River Jordan in accordance with British Royal tradition. His godparents are Nicholas van Cutsem, Guy Pelly, Harry Aubrey-Fletcher, Lady Laura Meade, Hannah Gillingham Carter, and Lucy Middleton.

During the ceremony, Louis wore the replica of the royal christening gown, created in 2008. It is a copy of the 1841 gown made for Queen Victoria's eldest daughter Victoria, Princess Royal, and used for every royal christening until it was retired for preservation in 2004.

In his young Royal career, Prince Louis has already made several official appearances. His first was on Jun 8, 2019, on the balcony of Buckingham Palace during Trooping the Colour. During the pandemic, he joined his siblings in an online video to applaud key workers. Again in September 2020, the children met David Attenborough. Kensington Palace then released a video of them asking Attenborough questions regarding environmental conservation.

In December 2020, they made their first red carpet appearance accompanying their parents to the London Palladium for a performance of a pantomime held to thank key workers for their efforts during the pandemic.

Prince Louis is fifth in the line of succession to the British throne, behind his grandfather (Prince Charles), father (Prince William), and older siblings, Prince George and Princess Charlotte.