Pretty confusing.

Since the day of their wedding, we have known Kate and William as the Duke and Duchess of Cambridge. The name suits them - but it won't be their name forever. When Prince Charles ascends to the throne of England, and becomes King, Kate and William will have a name change. Prince William will inherit his father's titles - and will be known as the Duke of Cornwall. William will also be the Duke of Rothesay when in Scotland. Needless to say, William will have a number of new titles, as will his lovely wife, Kate. Kate will take on all of the same title as her husband, but as a Duchess and Princess. Marlene Koenig, royal historian, recently explained to Hello! that William will always be the Duke of Cambridge; but may be styled as HRH The Duke of Cornwall and Cambridge. Kate would be HRH The Duchess of Cornwall and Cambridge, while their children would also be 'of Cornwall and Cambridge'. Interesting! Then there is the Prince of Wales title, which is not actually a given apparently. This title is not hereditary, and Charles did not become the Prince of Wales until he was nine. However, it is at the discretion of the monarch, so we can assume that Kate and William will become the Princess and Prince of Wales at some point!