• Princess Kate has several nicknames
  • One of them is a little side swipe
  • That's what Prince William calls her

Prince William's nickname for Kate, Princess of Wales is a "gentle reference" to the late Queen, according to a royal biographer. In his new book, Gilded Youth: An Intimate Story of Adolescence in the Royal Family, Tom Quinn explores the prince and princess' relationship behind closed doors.

Duchess Kate: That's why she was criticized by the Queen

A former member of royal staff who knew Prince William claims that the Princess of Wales called her husband "babe" while he sometimes calls her... "Duchess of Dolittle", among other pet names, according to the royal author.

Also interesting:

The latter - also known as "DoD" - is a "gentle dig" which refers to the late Queen Elizabeth II's criticism that Princess Kate did not have a full-time career before her marriage in 2011, according to Fox News.

But the Princess has her own jokes. Because of William's remarks about her "endless hair' Kate sometimes calls her husband 'Baldy', as reported by the Sun. William also calls his wife "babykins".

The Prince of Wales admitted in an interview with NBC in 2007 that his mother, Princess Diana, "wombat", a nickname he retained into adulthood.