Royal fans are ready to welcome Prince William and Kate's second child — a younger brother or sister to Prince George, whose birth two years ago whipped up a worldwide media frenzy.
As in 2013, the royals are keeping everyone guessing by disclosing virtually nothing about the baby — including the due date and gender.
If the bookies are to be believed, the baby will be a princess and she will be called Alice.
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Here's what we know — and don't know — ahead of the second royal baby's birth, expected in the coming days:
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MYSTERY BIRTH DATE
Clarence House announced on Sept. 8 that Kate was pregnant, but gave no clues about the due date other than to say it would be this month. On a recent public visit, Kate reportedly told a charity worker that she is due mid-to-late April.
The baby could share a birthday with her great-grandmother, Queen Elizabeth II, who was born on April 21. The newborn's birthday could also coincide with William and Kate's fourth wedding anniversary, on April 19.
Though there has been no confirmation of the baby's gender, bookies and the British media seem confident it will be a girl. Some suggest that Kate herself offered a hint of what's to come with her choice of clothing: She wore a bright pink coat for her final public appearance, before she disappeared for maternity leave.
As for what the baby will be called, many are betting on one quaint-sounding name: Alice.
The name is by far the favorite among Britain's bookmakers, with William Hill putting odds at 2-1 after a number of unusually large bets came in for it. Ladbrokes puts the odds at 3-1. No one seems to know why, though.
Elizabeth and Charlotte follow closely, with Victoria, Alexandria and Diana trailing behind. James and Arthur come in as the top bets for a baby boy.
"It's absolutely dominated at top of the market by girls' names," said Joe Crilly, spokesman for William Hill. "They're the seemingly perfect couple so maybe they'll have the perfect combination of a boy and girl family."
Britain's royal history has seen a few women called Alice: Queen Victoria named her second daughter Princess Alice, and the queen's mother-in-law — Prince Philip's mother — is Princess Alice of Battenberg.
Whatever the royals choose, it's fairly safe to rule out names like Wayne or Mercedes — both with odds of 500-1, according to Ladbrokes.
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HEIR OR SPARE?
When George was born in 2013, he jumped the line of succession ahead of uncle Prince Harry to become the third in line to the throne — after Charles, his granddad, and his father William.
George's sibling will become the fourth in line, bumping Harry down to fifth place. Prince Andrew, the queen's second son, moves to sixth.
As the second-born, the new baby will likely not be expected to become the ruling monarch. Instead, he or she will be the "spare," or backup, should anything happen to the first-born.
George VI famously became king unexpectedly after his brother, Edward VIII, abdicated in 1936.
"An abdication is highly unlikely to happen again, but you never know," says Joe Little, managing editor at Majesty magazine.
And unlike in the old days, the gender of the second child will not matter.
Britain in 2013 introduced legal changes to end a centuries-old "male primogeniture" rule that puts boys before girls in the line of succession. Under that system, a princess can be robbed of her place in the line by a younger brother.
That rule, which dates back to the 1701 Act of Settlement, is now abolished in Britain as well as in 15 former British colonies.
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Kate, 33, and William, 32, seem relaxed about the birth of their second child, and both have been out and about chatting with locals and keeping up their official duties until March.
Kate did suffer from severe morning sickness, or hyperemesis gravidarum, in the early months — just as she did during her first pregnancy — and had to pull out of plans to make her first solo royal tour to Malta. But her health improved since then, and she looked well as she was snapped by photographers wherever she went.
Meanwhile, William will be taking some paternity leave from his new job. The former search and rescue helicopter pilot began his full-time job with the East Anglian Air Ambulance on March 30, and is expected to begin flying rescue missions this summer.
THE BIRTH ANNOUNCEMENT
Britain's royal family may be one of the world's most traditional institutions, but its press team has made efforts to modernize communications by taking on Twitter and other social media.
Just like when George was born, royal officials plan to announce the baby's birth by Twitter, broadcasting the news directly to the monarchy's millions of followers worldwide.
Journalists will get a slight head start, though — reporters will get an email two minutes before the palace tweets the news.
About two hours later, officials will post a more traditional announcement on a gilded easel outside of Buckingham Palace.