Crowds gathered to catch a glimpse of the future King and his parents together in public for the first time since they left the Lindo Wing after the birth in July.
Prince George Alexander Louis of Cambridge, who looks remarkably like William as a baby, was content in his father's arms as he carried him into the chapel.
The new mum wore a cream Alexander McQueen coat dress with frill detailing and an elegant beret with a silk and lace veil by Jane Taylor for the occasion. The young family arrived by car with the third in line to the throne in his car seat in the back next to his doting mum Kate.
The Duke and Duchess of Cambridge are joined by senior members of the royal family including the Queen, Prince Charles and Prince Harry, the Middleton family and close friends including George's six godparents who were announced shortly before the ceremony.
William's cousin Zara Phillips is the only member of the royal family to be named as a godparent. The others are: Jamie Lowther-Pinkerton, the couple's former private secretary; Julia Samuel, a close friend of Diana's; Hugh, Earl Grosvenor, the son and heir of the Duke of Westminster; Oliver Baker, a fellow St Andrews student; Emilia Jardine-Paterson, the Duchess' best friend from Marlborough College; and William van Cutsem, one of William's oldest and dearest friends.