Princess Charlotte will go by a new name at school

Princess Charlotte is growing up right before our eyes!

Sept. 5 is set to be a big day for the four-year-old, who will join big brother Prince George for her first day of school! Charlotte will be dropped off at Thomas's Battersea by her parents Prince William and Duchess Kate to kick off a semester of computing, French, art, drama and ballet, in addition to her core studies.

The royal tot will also be taking a different name during her time at the $23,000-a-year prep school, dropping her official moniker of Her Royal Highness Princess Charlotte of Cambridge. Instead, she will be known as Charlotte Cambridge to her peers and teachers. Her brother also goes by George Cambridge, but has reportedly assumed the nickname P.G. from his classmates!

Technically, the royals' last name isn't Cambridge, but Mountbatten-Windsor. Like Charlotte and George, Prince William and Prince Harry dropped their official royal titles and surname when they started school, instead assuming the names of William Wales and Harry Wales after their father, the Prince of Wales.

Charlotte "can’t wait to be with George at big school!” said a source to People. She is "so excited about it all."