The Queen has decided that the Duke and Duchess of Cambridge, who are expecting their first child together this year, will be granted royal titles.
Up until now, if Kate gave birth to a baby girl she would have been given given the title of 'Lady,' while a boy would have automatically become a prince.
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A formal notice confirming the news was revealed in the London Gazette, announcing: "The queen has been pleased by Letters Patent under the Great Seal of the Realm dated 31 December 2012 to declare that all the children of the eldest son of the Prince of Wales should have and enjoy the style, title and attribute of royal highness with the titular dignity of prince or princess prefixed to their Christian names or with such other titles of honour."
Also, if Kate has twin boys or a second son at a later point, that second son would be treated as the son of a Duke - and therefore would not be an HRH.
Instead he'd be given a 'Lord' title.
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Kate, who celebrated her 31st birthday yesterday, is believed to be around 12 weeks pregnant.
Sadly it hasn't been the easiest of pregnancies for the Duchess, who has been battling hyperemesis gravidarum - a severe form of morning sickness.
However, royal insiders recently revealed she is "feeling much better" following a stay in hospital for the condition last year.