Prince George of Cambridge's third given name, Louis, could to be a tribute to Lord Louis Mountbatten, the Duke of Edinburgh's uncle and the last British Viceroy of India before independence in 1947.
Lord Mountbatten and William's father, Prince Charles, were very close - he was Charles' confidant.
He was known by the royal family as Uncle Dickie and was assassinated by the IRA in August 1979.
Louis is also the Duke of Cambridge's fourth name - he is named William Arthur Philip Louis.
The Queen's father George VI had Albert as his first name. Will Prince George also pick a different reigning name? He might.
The last British King to named George was George VI - Queen Elizabeth's father and the newly named Prince George's great great grandfather.
This picture shows King George VI standing behind the now Queen Elizabeth II. The Queen is holding her son, Prince Charles.
The Duke and Duchess of Cambridge have named their son HRH Prince George Alexander Louis of Cambridge.
Previous Georges who have become Britain's King are:
- George I - ruled August 1714 to June 1727
- George II - ruled June 1727 to October 1760
- George III - ruled October 1760 to January 1820
- George IV - ruled January 1820 to June 1830
- George V - ruled May 1910 to January 1936
- George VI - ruled December 1936 to February 1952
George VI was Queen Elizabeth II's father and George V was the Queen's grandfather.
In a statement, Kensington Palace said:
The Duke and Duchess of Cambridge are delighted to announce that they have named their son George Alexander Louis.
The baby will be known as His Royal Highness Prince George of Cambridge.
The Duke and Duchess of Cambridge have decided to call their son HRH Prince George Alexander Louis of Cambridge, Kensington Palace announced.
The Duke and Duchess of Cambridge will announce the name of their newborn baby shortly, ITV News understands.
Bookmakers William Hill have backed George as the favourite choice for the name of the Duke and Duchess of Cambridge's first child.
- George 2/1
- James 4/1
- Alexander 9/1
Anthony Adolph, an expert on the Royal Family tree, has told ITV News he believes Edward could be a potential name choice for the Duke and Duchess of Cambridge's son.
He also explained how the new Prince is "my tenth cousin, twice removed".