An official notice at the gates of Buckingham Palace in London on Monday announces the birth of a son to Britain's Prince Harry, Duke of Sussex and Meghan, Duchess of Sussex. (Yui Mok/Pool/AFP/Getty Images)

LONDON — Arthur? Alexander? Thor? Philip? Marvin? WINSTON? There’s a new royal baby in town, but what will his name be?

The Duke and Duchess of Sussex, more fondly known as Prince Harry and Meghan became parents to a baby boy on Monday. News of the birth of their first son, who is seventh in line to the British throne, came via Buckingham Palace and er, the couple’s Instagram account. Who says centuries of royal tradition and a modern day romance can’t mix?

Following the announcement, crowds gathered clutching balloons, champagne was popped and the words “It’s a baby boy!” glowed blue and danced around the top of London’s BT Tower. On social media, celebrities, politicians and royal fans around the world offered up their congratulations to the dashing ginger prince and the American-born Meghan Markle, who were married in May last year.

But what about the baby’s name. The Name. THE NAME???

For Meghan and Harry, a couple who have already broken with the pressures of royal tradition in so many ways, the naming of their firstborn has the world watching for several reasons: 1) well . . . it’s a royal baby! 2) this is the first interracial British royal baby in modern history 3) the baby is a dual citizen — will his name reflect that he is both a U.S. and British national?

For British bookmakers, who wrongly predicted the baby would be a girl, the current favorites are Alexander and the highly traditional: Arthur and Albert.

"I’ll back Alexander. It’s the new favorite as well. No well-known royal links. If they liked the name it would be a distinctive choice,” said royal commentator Richard Fitzwilliams.

Some royal fans say the chosen name could give a nod to the baby’s maternal grandmother, Princess Diana, who died in a Paris car crash in the summer of 1997. Princess Charlotte, first and only daughter of William and Kate, took Diana as one of her middle names when she was born Charlotte Elizabeth Diana, four years ago.

If Harry and Meghan were to follow William and Kate’s lead, many royal fans believe that the name Spencer — after Princess Diana’s side of the family — is another strong option. Earl Charles Spencer is Harry’s uncle and Princess Diana’s younger brother. He offered his congratulations to the new parents Monday, calling the birth “really very lovely news” on Twitter.

Sharing his views of the name Spencer, Fitzwilliams said: “Its links to the earl wouldn’t be popular with all the royal family, especially Charles, but I suspect the queen would also not be enthusiastic.”

Other popular names circulating are Charles and Philip, which would have ties to the baby’s paternal grandfather (who is next in line to the throne) and great-grandfather, Prince Philip, who is 97 years old. In the United States last year, the most popular boys’ names were Jackson, Liam and Noah. Whereas in Britain, the most popular boys’ name last year was Oliver followed by Harry and George.

On social media, users did not disappoint with their predictions. Some were sweet, some were unique and some were simply wild. From Thor to Jamal, Gavin to Gary, Marvin to Ashton, speculation was in full flow on Monday and doesn’t seem to be slowing down. Spider-Man also happened to be trending in Britain at the same time, although this is thought to be unrelated to the royal arrival.

But, there are many who think Meghan and Harry will go against royal tradition and pick a name more popular in America than “Arthur” — after all, Meghan was born and raised in the United States. Meghan is also deeply proud of her black heritage, although she has spoken out in the past about her struggle to understand her identity in her early years and how best to find her voice in the world as a mixed-race woman.

“While my mixed heritage may have created a gray area surrounding my self-identification, keeping me with a foot on both sides of the fence, I have come to embrace that,” she wrote for Elle in 2015.

Meghan, Harry and he-who-is-not-yet-named (at least, in public,) are expected to make their first appearance as a family on Wednesday. The baby’s name and title are also expected to be formally revealed. Contrary to popular belief, the child will not automatically assume the title of Prince unless Queen Elizabeth says so.

Until then, place your bets.