Updated April 23, 2018 23:31:36

Photo: Prince George and Princess Charlotte will soon have a baby brother or sister. (Twitter: Kensington Palace)

The Duchess of Cambridge has been admitted to hospital to give birth to the couple's third child and the latest member of Britain's royal family.

Photo: These royal fans hope they won't be kept waiting for too long. (Reuters: Henry Nicholls)

The odds are split on whether the new royal will be a boy or a girl, but bookmakers have been taking bets on a shortlist of possible names.

Royal expert Giselle Bastin from Flinder's University said William and Catherine had a little more room to play this time around, having already ticked all the right boxes with Prince George and Princess Charlotte, but her guess was that they would "play it safe".

"They certainly can't go for one of these new phonetically spelled, contemporary names. They'll still be Windsor names of one kind or another," she said.

That rules out any surprises but Dr Bastin said the Royal family was also very conscious of appearing too old fashioned.

"They have to go modern but they have to keep it traditional," she said.

So what names are in the running?

Photo: These are the odds for the royal baby name. (Reuters: Peter Summers)

Dr Bastin said members of the Royal family were traditionally named after their relatives and descendants.

Case in point was Princess Charlotte, who was christened Charlotte Elizabeth Diana after her grandfather Prince Charles, her great grandmother Queen Elizabeth II, and her late grandmother Diana.

For that reason, the possibilities include Alice, Mary, Elizabeth and Victoria if it's a girl, or Arthur, Albert, Philip and James if it's a boy.

Why those names?

Arthur hasn't been used as a first name in a while, and has strong royal connotations — think King Arthur and the knights of the round table. It would also reference both William and Prince Charles, who have it for a middle name.

Albert is another classic English name that means noble. It would pay homage to the Queen's late father, Albert "Bertie" Frederick Arthur George.

Philip is a less likely choice, given the royal family tends to avoid names already in use, but would be a sentimental nod to the Duke of Edinburgh and to Catherine's sister Philippa.

And James is an "outside" chance, according to Dr Bastin, as it's already the name of Catherine's younger brother, James William Middleton.

So no Zaras this time?

Photo: Zara Tindall is the daughter of Princess Anne and her former husband Captain Mark Phillips. (AP: Matt Dunham, File)

It's unlikely. When Princess Anne named her daughter Zara, it was considered a pretty unusual name for a royal.

But Dr Bastin said the rules were somewhat more relaxed for Princess Anne because her children wouldn't have the HRH (Her Royal Highness) title.

"They kept their commoner last name, so Princess Anne could really do anything she wanted with them," she said.

The story actually goes that Prince Charles suggested the name, which means "bright as the dawn" in Greek.

Are there any names that are off limits?

Dr Bastin said royal names could be tainted by former kings and queens, but history proved those grudges weren't held for very long.

For example, the Queen named her fourth son Edward even after her uncle King Edward VIII abdicated the throne in 1936.

But Dr Bastin said William and Catherine would likely still run their pick past the Queen first, just to be safe.

"Just in case there's a name where they don't know about any skeletons in the closet," Dr Bastin said.

When will we find out?

Thankfully, Kensington Palace won't keep us waiting for too long.

In 1982, Prince William's name was announced a week after his birth, but Princess Charlotte's name was announced after just two days.

Topics: royal-and-imperial-matters, human-interest, united-kingdom

First posted April 23, 2018 18:05:37