Bookmakers witnessed a betting frenzy as the Duke and Duchess of Cambridge edged closer to welcoming their baby into the world.
Coral said the royal baby was the biggest non-sporting betting event in the company's history and punters were rushing to wager money on every aspect.
Nicola McGeady, spokeswoman for the firm, said: "The whole world has been waiting for Kate to go into labour and now that she has, we have witnessed another betting frenzy.
"Punters have been anxiously clutching onto their betting slips for months now and if the money talks, the baby will be called Alexandra, with brown hair, weighing 7lb to 7lb 15oz, an outcome which will prove a nightmare result for the bookies."
Paddy Power said some £30,000 was taken in bets in the three hours following the announcement that Kate was in labour.
Bets on the birth date have been suspended. Odds on the name Isabel/Isabella were cut from 25/1 to 10/1 following large bets placed on the prospect it could be William and Kate's chosen name for a girl.
Paddy Power even opened bets on the colour of Pippa Middleton's dress if she visits the baby in hospital.
William Hill said it hoped the arrival was not a girl because of how well backed it was in their royal baby markets - when bets were suspended on the sex, the odds stood at 8/15 for a girl and 11/8 for a boy.
The favourites at William Hill for a girl's name are Alexandra (7/4), Charlotte (6/1) and Diana (12/1), while the most popular boy's names are George (8/1) and James (10/1).
William Hill spokesman Joe Crilly said: "Royal baby betting has been incredibly popular and it looks like we may finally be able to pay out on the markets. We are excited that the birth is imminent, we just hope the young one is not a girl named Alexandra."
The Archbishop of Canterbury, the Most Rev Justin Welby, tweeted: "My thoughts and prayers are with Kate and the whole family on this enormously special day."