The unique name was an unexpected choice as most royal experts speculated the Duke and Duchess of Sussex would pick a traditional regal name, like Albert or Philip.
Archie’s middle name, Harrison, is likely a sweet tribute to dad Prince Harry as it literally means “son of Harry.” Mountbatten-Windsor is a surname used by some members of the Royal Family.
Archie is an increasingly popular name in Britain and was among the top 20 most common boy’s names in 2017, according to the Office for National Statistics.
Archie is also rumoured to be cousin Prince George’s nickname.
WATCH: Meghan Markle and Prince Harry introduce son
In January, the eldest child of Kate Middleton and Prince William was reportedly on a walk with his grandmother, Carole Middleton, when he asked a stranger if he could pet her dog.
According to the woman, she wanted to engage in a bit of small talk with the prince so she asked him his name — despite knowing exactly who he was.
“To my astonishment, he said: ‘I’m called Archie’ with a big smile on his face,” the woman told the Sun. “I don’t know why he calls himself Archie, but kids often play with their names, and I think it’s lovely.”
Royal fans were placing name bets long before the child’s birth, and most people believed the Duke and Duchess of Sussex were having a girl. The top girl’s name was Elizabeth (6/1).
The top boy’s name was Albert (12/1), the name of Queen Victoria’s husband. Albert was also a top pick for Middleton and Prince William’s son Prince Louis, who was born in April 2018.
As few people expected Archie, people are sharing their reactions to the newest royal’s name on social media.
On Twitter, some are fans of the name and think Archie is great. Others are less impressed.
It is still unclear what official royal title Archie will have.
As of now, his title is likely Earl of Dumbarton, which he inherited from his father.
—With files from the Associated Press