3 December 2012 Last updated at 16:42 GMTHelp
The Duchess of Cambridge is expecting a baby, St James's Palace has announced.
Members of the Royal Family and the duchess's family, the Middletons, are said to be delighted.
A spokesman said the duchess has been admitted to King Edward VII Hospital in central London with very acute morning sickness and is expected to stay for several days.
Royal historian Kate Williams said whether boy or girl, the child will be next in line behind Prince William in the line of succession to the throne.