Bookmakers have slashed odds on Prince William and Duchess Catherine announcing they are expecting another baby.
Ladbrokes has cut the odds to just 4/6 that the royal couple - who have three-year-old Prince George and 17-month-old Princess Charlotte - will make an announcement next year stating they are to welcome a third child into the world.
It is 4/1 the pair will reveal such news before 2016 is out, or a 3/1 chance for a baby announcement to be made in 2018.
Jessica Bridge of Ladbrokes said: "The sight of Kate and Wills with George and Charlotte has sent royal baby watchers into overdrive.
"A 2016 announcement seems unlikely but if the money's to be believed 2017 looks like a certainty.
"Fans of the Duke and Duchess are hoping the couple make an addition to their gorgeous brood sooner rather than later."
William and Catherine, who are both 34, have recently returned from an eight-day tour of Canada with their children, and he thanked the Canadian people for welcoming his family into their country.
He said in a statement: "Catherine and I are incredibly grateful to the people of Canada for the warmth and hospitality they have extended to our family over the last week.
"We have loved our time in British Columbia and Yukon and will never forget the beautiful places we have seen and the many people who have been kind enough to come to welcome us in person.
"We feel very lucky to have been able to introduce George and Charlotte to Canada.
"This country will play a big part in the lives of our children and we have created such happy memories for our family during this visit.
"Canada is a country of optimism, generosity and unrivalled natural beauty. I hope we have helped all Canadians celebrate what makes this country great. We will see you again soon."