I was at the mall yesterday shopping at my favorite book store. I was looking at magazine and People this week had our lovely Duchess of Cambridge on the cover. But for some reason the American Press( I am American) call her Princess. She received the title of Duchess of Cambridge when she married Prince William. Prince William was giving the title of Duke of Cambridge from Her Majesty Queen Elizabeth II( His Grandmother). So therefore he and his wife are know as: Their Royal Highness Duke and Duchess of Cambridge. Catherine one day will be a Princess when her husband becomes the next Prince of Wales. When his father becomes King Charles. But that is not happen anytime soon in near future. So correct people say no Catherine is Duchess of Cambridge.
Here is the order from Her Majesty:
THE FOLLOWING STATEMENT IS ISSUED BY THE PRESS SECRETARY TO THE QUEEN
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 I like to say her Majesty has spoken!!!