Prince William has been made the Duke of Cambridge on his wedding day by his grandmother the Queen, Buckingham Palace announced.
The royal groom was given a dukedom - the highest rank in British peerage - to mark his marriage to Kate Middleton. Miss Middleton will now become Her Royal Highness the Duchess of Cambridge on her marriage at the much-anticipated ceremony in Westminster Abbey.
William also became the Earl of Strathearn and Baron Carrickfergus, which means Kate will become the Countess of Strathearn and Baroness Carrickfergus.
All titles are in the gift of the Queen and it was up to the monarch to choose which one to bestow on her grandson and his new wife. But William's thoughts will also have been taken into account by the royal matriarch in a private discussion between the Prince and his grandmother.
Tradition dictates that royal men receive a title on their wedding - and often more than one.
Buckingham Palace said in a statement: "The Queen has today been pleased to confer a Dukedom on Prince William of Wales.
"His titles will be Duke of Cambridge, Earl of Strathearn and Baron Carrickfergus. Prince William thus becomes His Royal Highness The Duke of Cambridge and Miss Catherine Middleton on marriage will become Her Royal Highness The Duchess of Cambridge."
As well as a duchess, Miss Middleton is also technically Princess William of Wales.
According to protocol, she is not officially Princess Catherine as she was not born a princess in her own right. Instead she adopts her husband's first name, in the same way as Princess Michael of Kent, who married the Queen's cousin Prince Michael of Kent.
But it is likely that in the eyes of the media and public, she could always be known as Princess Catherine or Princess Kate.