By Stephanie Petit and Simon Perry
Samir Hussein/Getty Images

Will Prince Harry and Meghan Markle spend this holiday season as an engaged couple? All bets are off!

Gambling companies have decided close bets on when an engagement between the 33-year-old royal and the 36-year-old actress will take place, amid gossip that an announcement is coming soon.

"The rumour mill is going into overdrive and it looks like the worst kept secret is to be confirmed imminently," Jessica Bridge of Ladbrokes, which suspended betting this week, tells PEOPLE. "It's long been a case of when and not if Harry and Meghan announce they are engaged, and all bets are off for a 2018 wedding."

The odds were 4/6 for the couple saying "I do" in 2018 before betting was closed.

On Tuesday, Company William Hill also closed betting on when the engagement will take place.

"Even at a very short price we were taking some serious money and chose to close the betting," said spokesman Rupert Adams. "We believe the happy couple are already engaged and possibly have been for some time."

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They are still taking bets on other factors of the relationship, like if Harry will shave his beard for the wedding (odds are now 4/6) and where the couple will walk down the aisle (St. Paul's is the front-runner, followed by Westminster Abbey).

Odds are currently 3/1 that the couple will have a child — a cousin for Kate Middleton and Prince William‘s children, 4-year-old Prince George, 2-year-old Princess Charlotte and a third baby on the way — by the end of 2018.

Markle, who reportedly just wrapped her last season on Suits, has already semi-immersed herself into London life during many under-the-radar trips to the capital. And she is now preparing for a more permanent move across the pond.

"Harry has made no secret of the fact that he wants to marry her," a source recently told PEOPLE. "She is the one."

During the last year, Markle has been spotted walking around Harry's neighborhood in Kensington, carrying Whole Foods shopping bags (the health food store is a short stroll from Harry's cottage), picking up flowers and visiting a spa in Soho on the eve of Pippa Middleton's wedding. But it was an invite to Buckingham Palace for tea with the Queen last month that is most indicative of how serious things are between the two.

The actress will live with Harry at his two-bedroom Nottingham Cottage in the grounds of Kensington Palace, where staff already know Markle. In a similar fashion, Prince William and Middleton lived together at St. Andrews university and then at a secluded farmhouse in North Wales briefly before they wed in April 2011. There has been speculation that one day Harry will move into Apartment 1 at the palace which has 21 rooms and is currently the home of the Duke and Duchess of Gloucester.

Many royal fans are wondering if Markle will spend Christmas with the royals this year.

Harry usually joins his family to celebrate Christmas with Queen Elizabeth, Prince Philip and the rest of the wider Windsor clan at the Queen's Sandringham estate. The private event which includes exchanging presents on Christmas Eve and a big lunch as well as a trip to church for Christmas services on the big day.

However, it isn't a guarantee that Markle will get an invite — even if they announce their engagement in the coming weeks. Kate wasn't invited to the festivities in Christmas 2010, despite the couple revealing they were engaged in November. They wed in April 2011.

Royalty expert Joe Little, managing editor of Majesty, tells PEOPLE, that his "instincts" are that she would not be invited. "I really don't think it will happen. Kate didn't go under the same circumstances," he says.

And even if Harry puts a ring on her finger before December, things might not be different. "There are some patterns that they seem to follow and I'm inclined to think that this is one of those," Little adds.

    This Story Originally Appeared On People