Is Diana's baby clock ticking?; It's well known that she desperately wants a little girl...now she's 36 and running out of time.
The sudden curves, big boobs and rounded tummy (as shown in our pictures on Page 3) have sent everyone from seasoned royal watchers to all the mums back home speculating about whether she could actually be pregnant.
Diana is 36 now and her biological clock is ticking. Her desperate desire to have a little girl is well known.
And while frolicking in the waves at St Tropez last week, she told reporters: "You are going to get a big surprise, you'll see."
If she was pregnant, the news would send shockwaves around the globe.
A baby would be about the biggest surprise she could come up with. But how else can the sudden change in her normally superfit body be explained?
Certainly no-one's body has ever undergone such excruciating examination as Diana's has in the past week.
Every day while she played with her sons at the palatial South of France home of Harrods tycoon Mohammed Al Fayed, the world was oohing and aahing over her new-found curves.
As Diana was finishing her holiday in St Tropez yesterday, the Sunday Mirror's Dr Mark Porter said he had at first thought she was in the first weeks of pregnancy.
It is no secret that the Princess would love to have a daughter.
The Sunday Mirror revealed last year that she had told close friends she wants to have more children.
And last month, she confessed to TV presenter Paula Zahn that she "would love to have another baby". Royal expert James Whitaker said St Tropez was abuzz with talk about the Princess as she prepared to fly today to Britain.
She was expected to fly by helicopter to Nice and then board a private jet owned by Al Fayed, who has also been her holiday host on his yacht.
Britain last week couldn't help but notice how happy she seemed to be showing off her new look.
But while most the beautiful people in the South of France have been wearing some of the tiniest bikinis ever seen, Diana put away HER bikini and opted for the less revealing one-piece look.
One of her circle said: ""The Princess was aware that people were commenting about her shape back home and didn't seem to mind.
It's quite a departure from the Diana of last year, who was livid at claims she had small traces of cellulite.""
Despite a variety of explanations for the new Diana - from excess eating to changes in her exercise regime - those closest to her understandably dismiss the idea of a pregnancy.
They feel that despite her erratic mood swings in recent weeks and the change in her shape in such a short time, the Princess would never allow herself to become pregnant yet. One explanation for her new shape came from Sunday Mirror diet and fitness expert Monica Grenfell.
"She is a naturally fleshy and big busted girl, although she has managed to keep it all toned up through years of exercising and dieting," said Monica.
"If you have dieted as severely as she has for years, when you give that up you go back to how you were before.
"And people who have been anorexic nearly always end up with big stomachs in later life.
"Perhaps she has been eating and drinking too much on holiday and hasn't been exercising as much as she used to.
"She's probably more relaxed about herself these days.""
"Monica added: "If you don't keep up stomach exercises daily you lose the ability to hold it in, and the more someone used to exercise the quicker they go downhill if they stop.
"Diana certainly has put on a bit of weight, but she still looks great. But she should watch it."
Speculation about Diana's future, which is as strong at Buckingham Palace as in the Princess's camp, comes as plans are made for the next meeting of the Way Ahead Group.
The Queen, Prince Philip their four children and senior courtiers meet twice a year to discuss new challenges facing the monarchy. Top of the agenda at the forthcoming meeting is Diana.
Diana's former royal in-laws are as intrigued as anyone at stories linking her to heart surgeon Hasnat Khan, who is still carrying out his life-saving work at London's Brompton Hospital.