The Duke and and Duchess of Cambridge have formally registered the birth of their son, Prince George.
Westminster City Council registrar Alison Cathcart travelled to Kensington Palace, where Prince William signed the birth register entry.
The Duke and Duchess gave their occupation as prince and princess of the United Kingdom in the register entry from which the birth certificate is produced.
Prince George was born on 22 July.
His full name of George Alexander Louis was announced two days later. He is third in line to the throne, behind his grandfather Prince Charles and his father, Prince William.
In a statement issued on Friday, Kensington 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."
The couple's "usual address" was listed as Kensington Palace, and the duchess's place of birth was listed as Reading.
A Kensington Palace spokesman said royal birth certificates conventionally featured the words prince and princess of the United Kingdom, or comparable formulations, as the parents' occupations.
Although Catherine uses the title Duchess of Cambridge, bestowed upon her by the Queen, she is also a princess by marriage and can be called Princess William of Wales.