Heads down against the breeze that blows across the peaks of the Lake District on the sunniest of days, the couple had their eyes on a distant hill.
Like other weekend walkers out on the fells last Saturday, Pippa Middleton and her boyfriend James Matthews paused to enjoy the magnificent views from the summit and to catch their breath.
But as Pippa took in the scenery, her romantic beau was dropping to his knees and preparing an even more spectacular sight - drawing out a stunning diamond ring from deep within a pocket.
Kneeling before her James asked Pippa to marry him. And within a moment she said "yes" and suddenly Britain's most eligible young woman was off the market.
Less than a year after she began properly dating the handsome hedge fund manager (they were briefly an item in 2012) the Duchess of Cambridge's sister is now engaged to be married.
Their wedding - almost certain to be held next year - will be the most glamorous and talked about match since Kate Middleton's to Prince William five years ago.
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It was the Royal Wedding in 2011, of course, that propelled Pippa to global fame after her star turn as her sister's chief bridesmaid and - thanks to a figure-hugging dress - the nickname of "her royal hotness".
The engagement, which I understand took the 32-year-old former party planner completely by surprise, has thrilled Kate and William and delighted the duchess's parents Michael and Carole Middleton.
Indeed I can reveal that Matthews, 40, asked Pippa's father for permission for his daughter's hand before popping the question. "James is a traditionalist and very much wanted to do things properly. That meant getting his future father in law's consent," a friend of the couple tells me.
Another family friend says: "Mike and Carole are very happy. They like James and they are sure he will make Pippa very happy."
Another friend told me Pippa was "completely and totally surprised" by the proposal but accepted it at once.
Their marriage will not just cement Matthews into the wider family circle that William and Kate have established, it will also link them to the celebrity world inhabited by James's brother Spencer, the coke-snorting louche lothario of reality TV show Made In Chelsea.
A tale of two very similar families
Intriguingly the union will connect two families with uncannily similar backgrounds. Like Pippa, James is the grandchild of a coalminer from the North of England.
Like Pippa, he boasts a parent of humble origin who has achieved considerable wealth: Carole Middleton is a former air hostess who grew up in a council flat, while James's father David, who made millions in the motor trade began his working life as a trainee mechanic in Rotherham.
Many will seize on both families rags-to-riches journey from working class ancestry to moneyed middle-class success as a shining example of the social fluidity of modern Britain.
For now, however, the engagement brings the curtain down on an even more engrossing story, that of Pippa's search for love which has been mesmerising us ever since that debut in her slinky Alexander McQueen frock outside Westminster Abbey nearly crashed Twitter.
In many ways there is almost something inevitable about the twisting romantic path that led Pippa to the tall good-looking Matthews. Even the fact that he's neither titled nor aristocratic, given the rather grand connections of some of her previous boyfriends, did nothing to minimize the feeling that many in her close circle believed he was "the one."
Rumours of their relationship first emerged last September when Matthews was spotted arriving at his grand Chelsea home with Ms Middleton late one evening and later taking his dog for a walk.
It came shortly after confirmation that Pippa had split from financier Nico Jackson after three years together. The following morning Pippa was photographed outside Mr Matthews' property clutching a bunch of red roses.
They were seen on a string of dates and since the end of December have been virtually inseparable. At New Year they spent eight nights on St Barts, the upmarket and super rich Caribbean island where James's parents own a fashionable hotel, the Eden Rock.
Close observers might have noticed that earlier last summer Pippa, her brother James and her mother Carole holidayed in the hotel. Matthews was also on the island at the same time.
At Christmas Mrs Middleton attended a carol service with Pippa and her boyfriend in Chelsea. By early this year Pippa's Range Rover was frequently spotted outside Matthews' £17 milliontown house which boasts a basement cinema and an underground car-stacking garage.
All the same neither Pippa nor James publicly confirmed their relationship, and, officially at least, Ms Middleton was said to be still sharing the Chelsea flat with her brother which they took over once Kate married.
Pippa's former flames
The society magazine
weighed in pithily describing James as a Rupert Everett lookalike "happiest when in a blazer and suede loafers."
It also suggested that Pippa had a thing for "tall men who work in finance" - both Jackson, whose parents run a sports shop in Folkestone and another beau, Old Etonian Alex Loudon had been similarly lofty City types.
Other squeezes included Jonathan "JJ" Jardine Patterson, whom she dated while at Edinburgh university and Billy More Nesbitt, whose mother Patrea was a former lady in waiting to Princess Anne.
It was also misheviously claimed that she had a relationship with the Duke of Northumberland's son Gorge (Earl) Percy, but they were just friends.
What drew her to Matthews, I understand, was his love for outdoor pursuits, particularly, running, swimming, skiing and cycling. "They love physical challenges," says a friend. "Pippa has swum the Bosphorus, climbed Mont Blanc and cycled across America. It makes them a good match. Earlier this year they completed 33 mile cross country ski race in Norway."
The man behind the hedge fund
But behind the conventional Sloane façade James Matthews is far more than a posh banker. For one thing, despite a privileged upbringing, his considerable personal fortune is almost entirely self-made. "He worked very hard from an early age," says a friend.
"He made a huge amount of cash from hedge funds and some more from the London property market. We're talking millions here and you don't do that by the age of 40 unless you are a sharp cookie. And James is very bright."
What makes this success all the more extraordinary is that for several years he could have pursued an altogether different career - as a racing driver. As a schoolboy James was one of Britain's most promising young drivers, achieving acclaim on the formula Renault circuit.
At 24, however, he suffered a family tragedy when his younger brother Michael died just hours after becoming the youngest Briton to scale Everest. His body has never been found and James often competes in marathons and exotic endurance races to raise money for a charity set up in his memory which helps provide education for children in Nepal, Thailand and Africa.
"With his parents out of the country in the Caribbean and his younger brother Spencer still a schoolboy, a huge burden fell on James," recalls a friend. "I have to say he was incredibly impressive.
"He's a smart chap but also the sort of bloke you would be proud to call a friend."
James cut his teeth in finance after leaving Uppingham, the £34,000-a-year Rutland public school whose old boys include Rowan Atkinson and Stephen Fry and Carphone Warehouse founders Sir Charles Dunstone and David Ross.
Instead of university he went to train as a trader at Spear Leeds & Kellog, now owned by Goldman Sachs.
At the same time he was gaining a reputation in racing first as a go-kart driver and then turning semi-professional. In 1994 aged 18 he won the British and European Formula Renault championship and there was talk of him trying formula 1.
Instead he chose finance - it was an inspired move. After joining a finance house called Nordic Options he rose rapidly to become the firm's senior equity options trader.
Then in 1999 - the year of the death of his brother - James launched his own firm Eden Rock Capital Management, named after his parents' hotel and based in Mayfair.
It quickly achieved success as a fund which invested in other hedge funds. By 2004 the firm looked after £131 million worth of investments. In 2007, the figure had risen to £1.1 billion.
The firm has an office in Bermuda and runs a network of overseas subsidiaries, some of them in tax havens. One subsidiary Solid rock Management is based in the British Virgin Islands.
But according to a close friend there is nothing opaque about his business. 'James pays his tax in the UK. His hedgefund is run as a partnership and the profits are distributed to the partners.'
The money he has made has provided an enviable lifestyle. In the early 2000s he lived in a property close to the US Embassy in Grosvenor Square before selling it and buying a house in Notting Hill whose previous owners included entrepreneur Nick Jones and his wife Kirsty Young, host of Desert Islands Discs.
Two years ago he paid £17 million for his current home in one of Chelsea's smartest streets. Earlier this year he applied for planning permission to add "his and her" dressing rooms off the master bedroom. He has his own private plane, a £3 million Pilatus PC-12 on which he whisked Pippa for a weekend away to Corsica in May
While James is said to be both serious and grounded, his brother Spencer is anything but. In a memoir Spencer claimed to have slept with 1,000 women, and dabbled with cocaine and LSD. Last year he drew more headlines after qutting I' m a Celebrity....blaming an addiction to steroids.
Of one thing we can be certain James's business acumen came from his father David. Raised in South Yorkshire by a former miner who had taken over a local garage, he first worked as a mechanic before taking up motor racing.
A glamorous figure - his first wife Nina was also a driver - he was forced into retirement after suffering serious injuries when he crashed at 130mph at Silverstone.
He then turned his hand to the second hand car business. His firm was taken over by bus and coach manufacturers Plaxton's which he then took over. In 1989 he engineered a second merger with giant car retailer Henlys leaving him in charge of a FTSE top 500 company. He left after buying the Eden Rock in 1995.
Later this summer James will accompany his fiancée to Switzerland where she is aiming to climb the Matterhorn - although he will not be making the attempt with her.
"Many people will say what a lucky guy James is for landing Pippa,' says a close friend, 'I would say she's the lucky one. He's one hell of a catch."
Last night a close friend of the couple told the Daily Mail: "I can confirm that Pippa and James are engaged. They are saying nothing more at this stage."