At a private dinner party shortly before Christmas, guests noticed that one of their number, a female member of the Royal Family, was particularly "glowing". She was animated and confident, relaxed and amusing.
Consequently she was on everyone's lips at the intimate post-mortems that usually follow such occasions. Why the surprise? Because the royal lady in question, Sophie Wessex, is usually perceived as earnest, but hardly sparkling.
And then some of those guests received this year's Christmas card from the Earl and Countess of Wessex. It bore two photographs. On the front, it had them standing together in front of a wooden cabin on the snow slopes of Finland, which they visited in February.
The surprise was on the card's back - a large picture of an ebullient Countess, in military fatigues, laughing in the snow as she lay at the entrance to one of the Finnish army's snow tunnels while trying out their survival skills course 80 miles north of the Arctic Circle.
For those dinner party guests, it was a reminder of a side of the Countess that the public seldom sees.
Such an effervescent glow could hardly be entirely attributed to the many hours she puts in doing Pilates or the five-mile runs she does twice a week with a personal trainer - though she is clearly pleased that she is slimmer now than she was four years ago.
Safest pair of hands
So what could have happened in the year since last January, when she reached 50, a difficult milestone for many women?
For the former Sophie Rhys-Jones, daughter of a tyre salesman and a secretary, it was a birthday that produced a huge wave of relief.
For the first time since she married Prince Edward in 1999, blonde Sophie has been able to feel completely free at last from the ludicrous millstone - which she hated - of being talked up as the apparent natural successor to Princess Diana.
In addition, the excitement of a second child for the Duchess of Cambridge has helped push Sophie, also a mother of two, even more to the margins of public life and inevitable scrutiny. Some royal figures might have viewed this as a crisis - but for Sophie, according to a close friend, it was "positively liberating".
For Sophie, who got things so badly wrong while still working in public relations when she joined the Royal Family, is these days viewed by the Queen as its safest pair of hands.
"She is trusted and relied on by the Queen in a way I couldn't say applied to the Duchess of Cambridge or the Duchess of Cornwall," says a royal aide. "She is like another daughter to Her Majesty, they are that close."
Their close relationship was visible for all to see when the pair travelled together by car to the private service at Sandringham at Christmas.
And with such closeness comes confidence. Certainly, Sophie is the only mother in the family who would dare over-rule her royal husband to forbid her eight-year-old son James - Viscount Severn - from joining in the royal shoots while young.
For Edward the seasonal shooting parties are an integral part of royal tradition, but James was noticeably absent from the Boxing Day shoot at Sandringham.
Nor is Sophie troubled, in the way royal women usually are, about slipping down the official rankings. For several years after marrying Edward, she was the second lady in the land to the Queen.
The subsequent arrivals of two new royal duchesses - Camilla in 2005 and Kate in 2011 - meant Sophie dropped down to fourth. (Were Prince Andrew to marry again, she would slip a further place to fifth.)
Filling a gap in the Queen's life
In what other royals would undoubtedly see as a further blow to their prestige, she no longer has full-time police protection. Nowadays, it is provided only when she is on official duties.
Edward is understood to have been furious when the change was made in 2012, and so was his brother Andrew on behalf of his party-going daughters, Princesses Beatrice and Eugenie, whose round-the-clock protection was also cut.
But Sophie, says a friend, was "entirely relaxed" about it.
"It meant they could live life as an ordinary family, which is how she was brought up in Kent. Sophie is at her most content when she is driving the children to school in her blue Jaguar and picking them up again at teatime."
Most significantly - as the Queen approaches her 90th birthday this spring - the closer she becomes to Sophie, the more she depends on her. "She talks to Sophie in the way she used to talk to Princess Margaret," says a palace aide.
"Sophie has filled a terrible gap in the Queen's life that was left when her sister and the Queen Mother died in 2002."
Touchingly, the Queen is doing much the same for Sophie, whose mother Mary died, aged 71, in 2005, by making sure that the Countess's 84-year-old father, Christopher, is included on the invitation list to many Royal Family events - a gesture that doesn't extend to the Middletons.
The Queen and the Countess also share a fascination with military history. Sophie loves listening to the Queen talk about great historical events, and the pair are sometimes gone for hours, poring over ancient documents in the Royal Archives, which are kept at Windsor Castle.
When Sophie visited the World War I and World War II battlefields and cemeteries in France, she told the Queen all about what she had seen and what she felt.
- Daily Mail