Prince William became the Duke of Cambridge today just hours before he marries Kate Middleton in a historic ceremony watched by million across the globe.
The announcement means Miss Middleton will become Her Royal Highness the Duchess of Cambridge when the happy couple are pronounced husband and wife by the Archbishop of Canterbury.
The Queen marked the royal wedding by giving her grandson the dukedom - the highest rank in British peerage.
The news came as hundreds of thousands of well-wishers poured into London eager for a glimpse of the wedding.
Early morning trains, usually all-but deserted on a Bank Holiday, were packed with royal fans, some wearing mock tiaras, most clutching Union flags.
They were rewarded with the news that the happy couple will brave the elements and travel from Westminster Abbey to Buckingham Palace in the open-topped 1902 State Landau.
As the bride and groom awoke after spending the traditional night apart, thousands of well-wishers were already lining the processional route from Buckingham Palace to Westminster Abbey.
Forecasters' warnings of rain showers over central London failed to dampen the mounting excitement.
Paddy Harverson, the Prince of Wales's communications secretary, said William was relaxed and having breakfast ahead of his wedding.
The Dean of Westminster, Dr John Hall, who is officiating at the ceremony while the Archbishop of Canterbury marries the couple, predicted "a tremendously warm and uplifting day".
Months of meticulous preparations will come to fruition as the couple marry in front of 1,900 guests and a global television audience of two billion, just after 11am.
The world will get the first full view of the bride's dress when she steps out of the Rolls-Royce with her proud father Michael.
Miss Middleton, 29, will walk up the aisle on her father's arm as a commoner.
Just over an hour later she will return back down, with her new husband by her side, as a member of the Royal Family and a future Queen Catherine.
Tradition dictates that royal men receive a title on the morning of the wedding and it was up to the monarch to choose which one to bestow on her grandson and his new wife.
The last Duke of Cambridge, like Prince William, married a commoner for love. He wed the actress Sarah Louisa Fairbrother in 1847.
William also became the Earl of Strathearn and Baron Carrickfergus, which means Kate will become the Countess of Strathearn and Baroness Carrickfergus.
Footage shows Kate Middleton arriving at her hotel in London yesterday.