Royal baby: Prince William, Kate Middleton introduce their princess to the world

A Town Crier makes the announcement that Catherine, Duchess Of Cambridge has given birth to a baby girl, outside the Lindo Wing at St Mary's Hospital on May 2, 2015 in London, England.

A Town Crier makes the announcement that Catherine, Duchess Of Cambridge has given birth to a baby girl, outside the Lindo Wing at St Mary's Hospital on May 2, 2015 in London, England. Image Credit: Getty Images

Prince William, Duke of Cambridge and Prince George of Cambridge arrive at the Lindo Wing after Catherine, Duchess of Cambridge gave birth to a baby girl at St Mary's Hospital on May 2, 2015 in London, England.

Prince William, Duke of Cambridge and Prince George of Cambridge arrive at the Lindo Wing after Catherine, Duchess of Cambridge gave birth to a baby girl at St Mary's Hospital on May 2, 2015 in London, England. Image Credit: Getty Images

Prince William, Duke of Cambridge, carries his newly-born daughter, his second child with Catherine, Duchess of Cambridge, as they leave the Lindo Wing at St Mary's Hospital in central London, on May 2, 2015. Image Credit: AFP

Prince William, Duke of Cambridge, carries his newly-born daughter, his second child with Catherine, Duchess of Cambridge, as they leave the Lindo Wing at St Mary's Hospital in central London, on May 2, 2015.

Catherine, Duchess of Cambridge holds her newly-born daughter, her second child with Britain's Prince William, Duke of Cambridge.

Catherine, Duchess of Cambridge holds her newly-born daughter, her second child with Britain's Prince William, Duke of Cambridge. Image Credit: AFP

Prince William, Duke of Cambridge, and his wife Catherine, Duchess of Cambridge show their newly-born daughter, their second child, to the media outside the Lindo Wing at St Mary's Hospital in central London, on May 2, 2015.

Prince William, Duke of Cambridge, and his wife Catherine, Duchess of Cambridge show their newly-born daughter, their second child, to the media outside the Lindo Wing at St Mary's Hospital in central London, on May 2, 2015. Image Credit: AFP

Sailors spell out SISTER on the flight deck of HMS Lancaster in a congulatory message to Britain's Prince William and his wife Catherine, Duchess of Cambridge after the birth of their baby daughter.

Sailors spell out "SISTER" on the flight deck of HMS Lancaster in a congulatory message to Britain's Prince William and his wife Catherine, Duchess of Cambridge after the birth of their baby daughter.Image Credit: Reuters

The London Bridge lit up in pink in honour of the new Princess.

The London Bridge lit up in pink in honour of the new Princess. Image Credit: Twitter

A computerised message stating 'it's a girl' is broadcast from the BT Tower announcing the birth of the royal baby girl.

A computerised message stating 'it's a girl' is broadcast from the BT Tower announcing the birth of the royal baby girl. Image Credit: Getty Images