Speculation over the couple’s potential impending marriage has been ramped up in recent weeks with the BBC reportedly primed for a Royal announcement.
Ladbrokes closed betting that Harry and Meghan would marry next year at odds of 4/6.
Spokeswoman Jessica Bridge told the Standard: “All bets are off when it comes to Harry and Meghan walking down the aisle next year.”
She added: “With the Duke and Duchess of Cambridge already expecting their third child, fans will be overjoyed at the prospect of two new arrivals into the royal family next year.”
The 36-year-old Suits star is rumoured to be moving to the UK after quitting the hit US show.
Reports have suggested she has already put her beloved pet dogs in transit and has been pictured in London increasingly frequently in recent months sparking rumours the pair are already engaged.
An Instagram post by Ms Markle’s former body double fuelled the fire.
Nicky Bursic, who has worked on the show for six years, posted a message on Instagram saying it had been an “honour” to be Ms Markle’s stand-in and that she was wishing her “all the happiness in the world”.
The post featured a picture of the pair standing beside one in another in matching outfits on the Suits set in Canada. She also tagged the message with a champagne glass emoji.
Mr Bursic’s message read: “It’s been an absolute pleasure and honour being your ‘stand-in’ for the last two seasons Meghan Markle. Though I’ve been on Suits for six years, the latter two has been my most memorable.
“Wishing you all the happiness in the world Bella. #youdeserveitall #loveher.”
Prince Harry has been dating the star of legal drama Suits since about May last year.
Rumours went into overdrive in mid-October when it was reported that Ms Markle and the Queen had met and spent an hour together in Buckingham Palace drinking tea.
Prince Harry and Ms Markle made their first public appearance together at the Invictus Games in September.