The thank you notes have already been written and the many changes of clothing – so much a part of a Sandringham Christmas – have been packed away for another occasion.
And judging by the warm words of old friends, an invitation to the next big Windsor gathering will not be long in coming to a woman who is not only ostracized but also blamed for many of the royal family's ills.
Of course she's been here before, but no one has perfected the art of the comeback like the Duchess of York. Usually a step forward is followed by a misstep and, as if she were a player in a game of snakes and ladders, she slides back down to start again.
But her presence and behavior as a guest at the King's Norfolk estate last week suggested she will not make the same mistakes this time.
Confident about the well-wishers who gathered to exchange Christmas greetings with Charles and his extended family, but not too confident.
Overjoyed: Fergie (second from left) at Sandringham with the Royals this Christmas
Sarah Ferguson gestures as she attends the Royal Family's Christmas service at St Mary Magdalene Church
Princess Diana with Sarah Ferguson in winter clothes in September 1988
Prince William and Kate and their three children were the big draw, but the audience's appreciation for the Duchess went beyond mere curiosity. Her redemption has been a long time coming.
The woman who was once amusingly called a breath of fresh air, whose indiscretions and extravagances – not to mention two flirtations with financial disaster – threatened to blow up the entire royal apparatus, has come a long way.
So this wasn't the fun-loving Fergie of old, who, just days after I witnessed her last public appearance at a royal Christmas 32 years ago, stunned her fellow passengers in the first-class compartment of an American Airlines transatlantic jet by giving her one Put the bag over your head and stick your tongue out.
All the years of exclusion that followed, during which she was kept alone in a manor house while the celebrations in the big house continued without her, suddenly seem like a distant memory.
Those were the days when Prince Andrew picked up his daughters on Christmas morning to go to church and then have lunch with their grandmother, the Queen, before taking them back to their mother after tea.
What exactly happened and why the sea change in the family's attitude expressed by Prince Philip, who described them as “pointless” (and much worse) and whose contempt for his former daughter-in-law was so great that he once jumped over a sofa in his haste to escape her?
To find the answer, one need look no further than the man who walked next to her in that churchgoing group on Monday – her ex-husband and devoted companion, Andrew, the Duke of York.
In the four years since Andrew's crash, no one has supported him more than former publishing company Girl Friday, who he fell in love with when they fed each other profiteroles at a house party at Royal Ascot almost 40 years ago.
After less than six years of marriage, they separated and divorced soon after. Since then they have remained happy together. They have lived on and off under the same roof, and when Andrew suffered the humiliation of having to give up his royal duties because of his links to sex offender Jeffrey Epstein, Sarah publicly defended him.
Stripped of his military affiliation and charitable patronage, Andrew was mired in a scandal over allegations – which he denied – that he had sex with teenager Virginia Giuffre (with whom he later reached a multi-million pound settlement), collapsing in public .
He became an embarrassment to the royal family and a laughing stock after his disastrous Newsnight interview in which he failed to express sympathy for Epstein's victims.
Sarah Duchess of York and Prince Andrew on the balcony of Buckingham Palace during their wedding on July 23, 1986
The Duchess of York on Loose Women on ITV on April 5, 2023
But his ex-wife's loyalty was beyond question. And that, as far as I know, was the essence of the king's simple gesture of bringing his former sister-in-law out of the cold.
“He has always valued loyalty and he appreciates everything Fergie has done for his brother,” says a friend of Charles. “It may be an exaggeration to say she kept him alive, but she definitely kept him sane.” Imagine what Andrew would be like without Sarah, who despite everything is one of the most optimistic about life?
Andrew, friends say, could easily have become a recluse, doing nothing but watching excessive television. Fergie refused to allow this. She encouraged him to exercise and continue his love of horse riding.
The King also admires the way the Duchess is restoring her own reputation while keeping her family together.
Thirty years ago she was the most reviled person in Britain – an overweight, overexcited, loose weapon. Her marriage had come to an ignominious end amid stories of infidelity, she had been pictured topless having her toes kissed by her “financial adviser” and her extravagance had left her £4 million in debt.
The royal family drove them out. It was a situation that would have devastated most people, and she admits it pushed her to the brink of a nervous breakdown. Somehow Fergie survived. She pulled herself together, cleaned up her personal life, lost four kilos, went to work and paid off her debts.
And then it happened again. More extravagance and more debt from failed money-making schemes, made worse this time by her falling victim to a dirty tabloid scam in which she tried to sell access to Prince Andrew for £500,000.
The yo-yo of ruin and disgrace, followed by survival and rehabilitation, became a well-trodden path for her. But more than a decade later, she has, as a friend puts it, “kept her nose clean, very clean.”
Then it was Andrew who helped her pay off her debts and allowed her to move back to the Royal Lodge, where she has her own suite of rooms. Now older and wiser – she turns 65 next year – Fergie has evolved into a considerate, mature woman.
The couple's daughters, Beatrice and Eugenie – now with children of their own – were also part of the royal's decision-making process. “He was always very fond of his nieces,” says someone close to him.
The royal was also touched by the way Fergie dealt with health setbacks. After a routine mammogram earlier this year, she was diagnosed with breast cancer and underwent a mastectomy and reconstructive surgery.
Rather than remain silent on such a troubling issue as the royals traditionally do, Fergie spoke out and her actions are said to have encouraged more women to make appointments for check-ups.
Princess Diana and the Duchess of York watch a polo match in Windsor, Berkshire
Sarah Ferguson, Duchess of York, arrives for the Christmas service at St Mary Magdalene Church, Sandringham
So what should we make of Charles' royal gesture and what does it tell us about Fergie's future? “I think we’ll be seeing Sarah more at these extended family events,” says a friend. “Don’t expect to see her on the balcony of Buckingham Palace after Trooping The Color, but Royal Ascot could be there on the other side.”
There's another fascinating part of this new dynamic – the role of Queen Camilla. “It's thanks in no small part to the new Queen that the royal family treats newcomers very differently these days.” She's also one of those “let it be bygones” people and takes a lot of time for Fergie, who she finds amusingly eccentric.”
However, one thing will definitely not happen: the Duchess will not resume royal life. She has her own charity streams. Earlier this month she made an unannounced visit to Burnley, where her charity Sarah's Trust was handing out gifts to disadvantaged children. She also traveled to Ukraine three times and accompanied trucks full of relief supplies.
Aside from philanthropic issues, there will be more television – she appeared on Loose Women and Lorraine Kelly this year and co-hosted This Morning – and more romantic fiction from Mills & Boon; Discussions are underway about adapting her first two books into possible screenplays.
As for Andrew, having Sarah as a more visible presence by his side may not change his reputation overnight, but it could be a start.