Prince William and Kate have sent individual thank you notes to well-wishers to mark Prince Louis' birth. The front of the card featured the official photograph of Louis, which was released by Kensington Palace in May. The note read: "The Duke and Duchess of Cambridge were very touched that you took the trouble to write as you did on the birth of their son, Prince Louis. Their Royal Highnesses are most grateful for the wonderful messages they have received and send you their warmest thanks and best wishes."
The lovely picture, which was taken by the Duchess, showed the baby Prince dressed in delicate white and propped up on a cosy cushion. The photograph was released alongside another image of the royal baby with his older sister Princess Charlotte, who was seen giving him a tender kiss on the head. Prine Louis, who is fifth-in-line to the throne, is the third and youngest child of William and Kate. The Duchess gave birth on 23 April in London and has been keeping a relatively low-profile since.
MORE: The reason why Prince William and Kate have chosen to christen Prince Louis on 9 July
The couple welcomed their baby boy on 23 April
On Wednesday, Kensington Palace announced that Prince Louis will be baptised on 9 July. According to an official statement, the christening will take place in the Chapel Royal at St James's Palace - the same place where Louis' big brother Prince George was baptised. The service will be conducted by the Archbishop of Canterbury and the Most Reverend Justin Welby, who also baptised George and Charlotte.
GALLERY: Prince William's sweetest dad moments with his children
Members of the royal family are expected to attend including the Queen, Prince Charles, the Duchess of Cornwall, Prince Harry and Meghan Markle. Kate's parents Carole and Michael Middleton, her younger brother James and her younger sister Pippa, who is pregnant with her first child, are also expected to make an appearance.