(CNN) -- "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 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, with an article detailing the treatment that 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 Sun's graphics department produced composite images of what they speculated the royal baby would look like as a baby of either gender, while the Mail ran mock-ups created by a U.S. forensic artist imagining how the child might look as a young boy or girl.
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.
UK tabloid the Daily Express, in a "royal souvenir special" edition, ran a piece speculating that it was more likely that Catherine was carrying a girl, or twins, citing research that linked those outcomes to morning sickness.
Bookmakers also 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. Brooklyn and Chardonnay were listed as long shots by bookmakers.
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's hair color, with one offering brown at 6-4 and red at 8-1, and another offering odds on the likelihood of an albino royal baby.
Bookmakers were also taking bets on the child's birth weight, and the identity of the godparents.
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 voice their happiness at the news. British Prime Minister David Cameron was swift to offer his congratulations.
PM: "I'm delighted by the news that the Duke & Duchess of Cambridge are expecting a baby. They will make wonderful parents." #royalbaby— UK Prime Minister (@Number10gov) December 3, 2012
Businessman Richard Branson joined the well wishers.
Congrats to Kate & Will on expecting your first child. The happiest day of your life to look forward to!— richardbranson (@richardbranson) December 3, 2012
Former Wimbledon tennis champ Boris Becker tweeted a picture of himself giving two thumbs up with a message of congratulations.
Two thumbs up to Will and Kate on their baby news. I wish them both the very best.— Boris Becker (@Becker_Boris) December 3, 2012
The news prompted responses from U.S. celebrities as well, with reality TV star Kim Kardashian tweeting her delight at the reports.
Awww so cute! Congrats!!! RT @KhloeKardashian: Congratulations to the Duke and Duchess of Cambridge!! A royal baby!!! :) awwww so sweet— Kim Kardashian (@KimKardashian) December 3, 2012
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 royal specials.
"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.