"A nation's joy, a husband's nerves," exclaimed Britain's Daily Mail newspaper, as it contrasted Prince William's anxious wait at his pregnant wife's bedside with the excitement generated by news of her impending motherhood.
The revelation that Catherine, the Duchess of Cambridge, was pregnant came after she was admitted to hospital in London on Monday afternoon suffering acute morning sickness.
The newspaper said the royal couple had hoped to keep their baby news under wraps until Christmas Day when she had passed the 12-week mark in her pregnancy.
"Kate expectations," declared popular British tabloid, The Sun. Its online edition then went with "Pregnant Kate on a drip," referring to the treatment Catherine, 30, was receiving for hyperemesis gravidarum, a condition that causes more severe nausea and vomiting than typical morning sickness.
The newspaper said even senior royals, including Queen Elizabeth II, were taken by surprise as the couple had yet to break the news to family.
The Times also led with news of Catherine's hospital dash, splashing a picture across its front page of a concerned William leaving London's King Edward VII hospital last night. The paper also joined the rush of feverish debate about the future royal's sex, potential name and position in the royal line of succession.
Boy or girl, the new baby will be third in line to the throne, behind William and his father, Prince Charles, who will become a grandfather for the first time. The Times explained that an imminent change to the law means that if Catherine has a girl, the child will make history by being the first British princess not to suffer discrimination because of her sex.
Bookmakers look set for a royal bonanza, with Victoria, Frances and Mary among the frontrunners for the most likely girl's name, though the odds that William's first-born child will be named after his late mother, Diana, Princess of Wales, have been judged at between 9-1 and 12-1, The Times said.
However Elizabeth is the hot favorite at 8-1, according to leading British bookmaker, Ladbrokes.
Ladbrokes has Charles and John at 10-1 when it comes to boy's names, but Harry, the name of the baby's uncle, is a distinct outsider at 33-1.
Bookmakers are also taking bets on the baby hair color, with William Hill offering brown at 6-4 and red at 8-1. Paddy Power, another British betting agent, is even taking money for guessing the baby's weight.
As expected, the name game is a white-hot pastime on social media, with #royalbabynames and #royalbaby among the biggest trending hashtags on Twitter. Among the more amusing suggestions were Cheryl and Jedward, reflecting Britain's recent obsession with television talent shows.
Twitter was also a popular destination for celebrities and public figures alike to give their thumbs up to the news. "I'm delighted by the news that the Duke & Duchess of Cambridge are expecting a baby. They will make wonderful parents," read a post from British Prime Minister David Cameron.
"Pope joins Twitter, Royal baby.... just need Arsenal to sign Messi now and my day is complete," tweeted CNN's British anchor Piers Morgan.
"Congratulations Kate Middleton and Prince William. I'm gonna have another cousin!" exclaimed U.S. stand-up comedian and TV host, Ellen DeGeneres.
"Awww so cute! Congrats!!! Congratulations to the Duke and Duchess of Cambridge!! A royal baby!!! :) awwww so sweet," tweeted American reality TV star Kim Kardashian.
News of the royal baby also grabbed column inches internationally.
"Royal baby a bonus for special editions," declared The Australian, as it predicted that Australian women's magazines would now go into coverage hyperdrive with a series of special royal editions.
"Royal Baby a 'Delight,' Especially to Britain's Tabloids," ran the headline in The New York Times. The paper's Sarah Lyall observed that "speculation began virtually the moment Kate Middleton said 'I will' to Prince William in April 2011, leaving an industry of tabloid newspapers and gossip magazines with a big black hole where their wedding coverage used to be."
Lyall said those who had previously -- and incorrectly -- guessed something was afoot because Catherine was drinking water instead of wine at some official dinner could now finally claim to be right.