Prince Harry and Meghan Markle revealed the name in an Instagram post Wednesday that showed Queen Elizabeth and Prince Philip meeting the tiny tot. Archie is a shortened version of the English and German name "Archibald," and means "genuine" and "bold," according to Baby Centre U.K.
Harrison means son of Harry, which is literally perfect.
(Funnily enough, Archie is also the nickname Prince George — the new baby's cousin — reportedly goes by when he introduces himself to strangers).
The name took royals fans by surprise, as neither Archie nor Harrison were in the top 10 running guesses on betting sites (although a few other "A" names were popular options, including Albert, Alexander, and Arthur). But some have pointed out it may be a nod to Meghan's African-American heritage, following in the footsteps of African scholar Archie Mafeje, African-American engineer Archie Alexander, and African-American musicians Archie Shepp and Archie Bell.
Archie is also a popular name in Britain, ranking in the top 20 for boy's names in 2017, the Associated Press reports.
In giving their baby the full name Archie Harrison Mountbatten-Windsor, Meghan and Harry have opted out of also giving him a royal title. He'll be known as Master Archie Mountbatten-Windsor, HuffPost U.K. reports.
"They have chosen not to use a courtesy title," a royal source said.
Earlier in the day at a photo call, the world also got its first peek of the littlest royal as he slept serenely in his father's arms.
"It's magic, it's pretty amazing," Meghan said Wednesday. "I have the two best guys in the world so I'm really happy. He has the sweetest temperament, he's really calm."
The new baby that was born Monday morning is seventh in line to the throne, and Queen Elizabeth's eighth great-grandchild. The couple made the birth announcement on their Instagram account, just minutes after the palace announced Meghan Markle was in labour.
The baby was born at 5:26 a.m. local time and weighed seven pounds three ounces, the palace confirmed in a statement. On Monday, Harry told reporters they were still thinking about names.
"The baby's a little bit overdue, so we've had a little bit of time to think about it," Harry said.
"That's the next bit."
WATCH: All the baby name theories, ranked. Story continues below.
While Meghan and Harry have been notoriously private about the details of their pregnancy, that hasn't stop people from gleefully guessing what they might call their first child. And, as usual, betting companies got in on the action.
The frontrunners were often girl names, as odds were on the royal baby being a girl, and many of them were family names, including Harry's mother, grandmother, and grandfather. Diana, Grace, Allegra, and Elizabeth were in the top spots on betting site Coral las week, followed by Arthur, Alice, James, and Philip. Grace and Diana also led the odds on Ladbrokes, and Diana and Victoria were the top bets on OddsChecker.
After it was revealed Monday that Meghan and Harry's baby was a boy, all those girl names went out the window and the names Alexander, Spencer, Arthur, James, Philip, and Arthur dominated the bets, according to the betting site Coral.
Spencer was Princess Diana's maiden name.
While these traditional names were the most popular with bet-makers, many pointed out that Markle, who is American, might select a popular U.S. name like Emma or Liam. Plus other royals have picked less traditional names for the kids. Peter Phillips' and Autumn Kelly's kids are Savannah and Isla, after all.
Harry and Meghan have a little more freedom with their baby-name choices since their child is seventh to the throne. But many also believed they would pay tribute to Harry's mother, the late Princess of Wales, Diana. Prince William and the Duchess of Cambridge honoured Diana and the Queen with Princess Charlotte, whose full name is Charlotte Elizabeth Diana.
Their third child, Louis Arthur Charles, pays tribute to Prince Charles (who also has Arthur in his middle name). Prince George, whose full name is George Alexander Louis, will eventually be the seventh King George in the U.K.
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