The Duke and Duchess of Sussex have wished their followers a “very Happy Thanksgiving from our family to yours”.
Their SussexRoyal Instagram account featured a message on a navy background under the couple’s monogram.
It read: “Wishing you a very Happy Thanksgiving from our family to yours – Their Royal Highnesses The Duke and Duchess of Sussex”.
It was followed by the comment “Happy Thanksgiving!” and a maple leaf emoji.
Harry and Meghan are celebrating their first Thanksgiving with their baby son, Archie.
It is not clear whether Harry and Meghan have invited the duchess’s mother, Doria Ragland, to spend time with them in the UK or whether they have travelled to the US for the American national holiday on Thursday.
The maple leaf is the national symbol of Canada – but the emoji is also used in Thanksgiving posts to denote the season.
The Sussexes are not taking part in a major gathering of the British monarchy next Tuesday, when the Queen will lead her family in welcoming Nato leaders, including US President Donald Trump, to Buckingham Palace for a reception marking 70 years of the alliance.
The couple are on an extensive festive break, thought to be six weeks, after a tumultuous year capped by the duke making a dramatic defence of his wife and attacking sections of the press he accused of bullying her.
It has already been announced that Harry and Meghan will not be spending Christmas Day with the Queen, Duke of Edinburgh and the rest of the royal family at Sandringham in Norfolk.
The Queen is said to be supportive of their plans, and it follows the Duke and Duchess of Cambridge’s past decision to spend Christmas with Kate’s parents, and not with the monarch.
In a recent documentary, the couple revealed their state of mind and the struggles they faced as newlyweds and new parents, living in the public eye.
The ITV programme, filmed during the Sussexes’ visit to southern Africa in October, featured Harry saying he and his brother William are now “on different paths” and have “good days” and “bad days” in their relationship.
Meghan described the past year as a member of the royal family as “hard”, and said her British friends had warned her not to marry Harry.
The duchess told the programme she had tried to cope with the pressures of her new life by putting on a “stiff upper lip”, but she was not prepared for the intensity of the tabloid interest.
On Wednesday, the couple marked two years since their engagement was announced, sharing images of their November 2017 photocall, a behind-the-scenes wedding picture, and one of newborn Archie Harrison Mountbatten-Windsor’s first public appearance when he was two days old.
Ms Ragland visited the UK when her grandson was born in May.
The yoga instructor and social worker could be hosting Harry and Meghan at her home in California.