For most of her 95 years, the festive season has without doubt been the most treasured time on the Queen's calendar.
She decamps to her beloved Sandringham Estate – a property that was also a favourite of her father, King George VI, who passed away in his sleep there in 1952 – throughout the duration of the British winter, where the royals traditionally gather for the holidays.
It's here that fans are usually treated to a brief sighting of the family on Christmas morning as they attend the nearby church, St Mary Magdalene.
This year, though, there will be one person missing – the Queen's husband, Prince Philip, Duke of Edinburgh.
Sources tell Woman's Day the Queen's preparations for her annual family gathering have been "noticeably tinged with sadness" for the monarch, after Philip died aged 99 in April.
They had been married for 73 years, with the Queen marking their 74th anniversary last month alone.
"Toward the end of Philip's life, they whiled away countless hours together on Sandringham estate, where he took to living in a small hunter's lodge away from the main property," says a source.
"It was a precious time for her, when they sat together on his porch under blankets and looked back on all they had created together.
"She will no doubt feel emotional returning to Sandringham, where Philip was last his active, witty self, and where her darling papa passed away so many years before that."
Not for nothing, though, has the Queen earned a reputation for "keeping calm and carrying on" during her record-smashing 69-year reign.
"Her Majesty is not an outwardly emotional person but she has confessed that this Christmas feels a little different without her husband," says a source.
"Philip's banter and cheeky quips will be missed by the whole family, but especially for the Queen.
"However, she is determined to continue her tradition of hosting the family – especially given they couldn't make it last year because of the pandemic – and plans on making it the best celebration yet, just as Philip would have wanted her to.
"She has a large group of adorable great-grandchildren now and she's anxious that the show must go on for them.
"That said, she has asked that the room that was once Philip's remain empty of guests as a mark of respect."
Christmas at Sandringham is traditionally a three-day affair with a strict roster of meals, gatherings and activities that can require a mind-bending five to seven outfit changes per day.
The festivities kick off on Christmas Eve, with tea and sandwiches served as the Queen's relatives arrive, before a gift exchange with the children and a luxurious dinner for adults.
There are several more meals over the course of three days, including champagne brunches, roast dinners and picnics during shooting expeditions.
"For the Queen, it's a chance to thank her entire family for their support over the previous year," says a source. "And never before has that been more important to her.
"Most of her family – the Sussexes perhaps not withstanding – have been her rock this year since Philip passed. They've made sure she never has to attend a public engagement alone and the Queen is ever so grateful to them all.
"She's not the type to shower everyone with expensive gifts, but the Christmas celebration will be extremely personal, with everyone's favourite food and drinks represented, that she is overseeing personally."
While the Queen may be focused on giving her family the best Christmas ever, insiders say her children, Prince Charles, Princess Anne, Prince Andrew and Prince Edward, will be watching their mother closely after she's suffered a spate of recent health scares.
In October, she was admitted to a London hospital under a shroud of secrecy – aides even left the flag signifying the sovereign's presence flying at Windsor Castle – where it was later confirmed she was undergoing tests for a mystery condition.
And last month, just as she was due to return to public duty, she was a last-minute omittance from Remembrance Day events.
"Once you get to 95, it's not quite as easy as it used to be," Charles, 73, admitted recently.
"The Queen's family are rallying around to ensure she's happy and healthy for Christmas.
"It's going to be a precious one, as they're all too aware that there might not be many left with her," says an insider.
"They've been blessed with having her in excellent health for so long, that her being unwell has come as rather a shock to them.
"They'll be keeping an extra close eye on her at Sandringham to make sure she doesn't overexert herself.
"Princess Anne and [the Queen's daughter-in-law Sophie] the Countess of Wessex have taken it upon themselves to help her out as much as they can, along with a team of long-time, trusted staff including her dresser and assistant, Angela Kelly.
"The Queen is surrounded by some very lovely people who are there to help her every step of the way, and to ensure it will be a Christmas that creates precious memories for everyone, and is a comfort to the Queen after losing her husband."