Bookmakers were quick to come up with a shortlist of likely names for the royal baby, with family names like Elizabeth, Diana and Charles ranked among the favourites.
Early odds also rated Frances and John among the top options for the son or daughter of the Duke and Duchess of Cambridge.
William Hill predicted that excited punters could bet up to £1m (€1.2m).
Ladbrokes said the royal couple naming their baby Elizabeth after her great-grandmother, the queen, was the 8/1 favourite, with Frances, John and Charles all on 10/1.
People wanting to place a bet on the child being called Diana, after William's late mother, were offered 12/1.
Jessica Bridge, of Ladbrokes, said: "Kate and Wills pulled the wool over our eyes, but now attention turns to the name of the baby and it looks like the couple will stick with a traditional name."
Paddy Power had Mary, Victoria and John on 8/1, with Diana and Frances on 9/1. It rated Camilla, the name of William's stepmother, as an unlikely 66/1 and Fergie as an outside chance on 250/1. (© Daily Telegraph, London)