Two weeks after his arrival and Prince George - the future King - has formally been registered.
New dad Prince William signed his son's birth certificate at Kensington Palace this morning (Friday, August 2).
Westminster Council registar Alison Cathcart travelled to the palace so William could sign the document. Kate and George are still believed to be staying with her parents in Berkshire.
A brief statement from the palace said: "The Duke and Duchess of Cambridge have formally registered the birth of Prince George. The Duke of Cambridge signed the birth register at Kensington Palace this morning, witnessed by a Registrar from Westminster Register Office."
Speaking about her Royal role, Alison said: "It was of course a great pleasure to work with Kensington Palace in arranging the signing of the birth certificate for Prince George.
"This cements an association with Westminster City Council and royal births in the borough that goes back decades. We registered the birth of the Queen and Prince Charles and Princes William and Harry so it's great to see that tradition continue.
"We can now add Prince George to that collection and again congratulate the Duke and Duchess on the birth of their son."