What is Prince Louis’ surname and is he a Cambridge like brother George?
PRINCE William and Kate Middleton named their third child Louis Arthur Charles.
Here's everything you need to know about the fifth in line to the throne's name, and what the prince's surname is...
What is Prince Louis' surname?
According to the royal family website, the surname of any child born to William and Kate would be Mountbatten-Windsor, which has been the official surname for the Queen's descendants since 1960.
The Queen after her accession to the throne in 1952 decided all of her descendants should distinguished from the rest of the royal family so combined the surnames of herself - Windsor - and her husband - Mountbatten.
So when any future relatives needed to use a surname, it would be Mountbatten-Windsor.
But kings and princes have historically taken their surnames from their dad's titles - so as William is the Duke of Cambridge, Louis has taken that as a last name like his brother George.
It is the same as when William and Harry took the name Wales in the military thanks to their father's title, Prince of Wales.
Is Prince Louis a Cambridge like brother George?
He is.
When George started St Thomas school in September, it was announced he would be registered as George Cambridge.
If the same applies to him, now three, his full name would be Louis Arthur Charles Cambridge.
At present, his official title is His Royal Highness Prince Louis of Cambridge.
Who is Louis Arthur Charles named after?
The name is a tribute to Prince Charles' beloved great uncle Lord Louis Mountbatten.
He was a close adviser to the prince and introduced the Queen to Prince Philip.
Lord Mountbatten was murdered aged 79 by the IRA, who planted a bomb on a boat at his summer home in Mullaghmore, Ireland, in August 1979.
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The middle name of Arthur is thought to be a nod to the legendary King Arthur and is also one of William and Charles' middle names.
It was also a middle name of King George VI - the Queen's father.
Charles is a sweet nod to William's dad Prince Charles and could also be a reference to King Charles I and King Charles II.