The Duke and Duchess of Cambridge have left hospital after the arrival of their third child, a boy, BBC reported.

The couple's second son, who was born at 11:01 BST, weighing 8lb 7oz, is fifth in line to the throne.

Prince George and Princess Charlotte had visited their brother at the Lindo Wing of St Mary's Hospital, London.Leaving the hospital Prince William said the couple were very happy, before holding up three fingers and joking he had "thrice the worry now".

Minutes earlier, Prince William and Catherine had come out of the hospital briefly to greet the crowds with their new son. They then returned inside to put their newborn son in his car seat before driving away towards their home Kensington Palace.

The prince is here! The Duke and Duchess of Cambridge appear on the steps of St Mary's Hospital with their third child #RoyalBaby pic.twitter.com/KfeypuiZ3G

— Sky News (@SkyNews) April 23, 2018

Princess Kate steps out with Prince William and the newest addition to the royal family. The couple welcomed a baby boy this morning: https://t.co/Ilq1wQh3po pic.twitter.com/4xU7YJE1Tz

— ABC News (@ABC) April 23, 2018