William and Kate waited four days to announce his name.
On Friday, that announcement finally came via an official statement from Kensington Palace, which read, "The Duke and Duchess of Cambridge are delighted to announce that they have named their son Louis Arthur Charles".
Though some thought the name was ironic given that Louis was also the name 18 kings from across the Channel, it turns out that the name Louis holds a lot of significance in the Royal Family. He will also share the middle name of Arthur with his father.
Prince Louis' name (which means "renowned warrior" in French) may have been chosen to honor Prince Phillip.
Prince William and Princess Kate have announced the name of their third child: Louis Arthur Charles.
GETTY PRINCESS CHARLOTTE Today is her third birthday
"It's unlikely they'll be asleep when William and Kate arrive home. I was so chuffed to see the baby's name.' And the links extend to Louis" sculptor dad Chris, 57, who created a pedestal for a bronze bust of the Queen which sits in Westminster Palace.
"The Duke of Cambridge is honoured to have been asked, and is very much looking forward to supporting his brother at St George's Chapel, Windsor on May 19th".
"Thrice the worry now", William told reporters, holding up three fingers with a smile, as he got into a Land Rover to take his wife and newborn back to Kensington Palace.
It was signed today by Prince William.