And here Andy shakes his head at the injustice of it all. "She was just attention seeking."
And so it came to pass that HRH The Duke of York climbed the steps to Pall Mall's bookish gentleman's club, only to be jumped by a bare-breasted lovely clad in transparent cape, feathery mask and G-string. The Prince looked agog; the paparazzi called it a night.
"I was really quite furious," says Andy. "It was really not on."
But then, the Prince was a long way from Sunninghill Park. Each year, Andy Wong, 36, and his wife Patti, 34, take it upon themselves to host London's most garish party. Nominally held to usher in Chinese New Year, it takes place in the last week of January. Not because that's when Chinese New Year is, you understand - they're a fortnight early - but because, Andy says, "everyone goes skiing in February". And by everyone, he means the social set around which the Wongs don't as much circle, as move in one eternal loop; gliding from country to country, event to event, as the social calendar dictates. So, once a year, why shouldn't they throw the mother of all parties for 700 of their closest acquaintances? "We like to be generous to our friends," says Andy.
The Wongs are the millionaire offspring of Hong Kong banking big shots. Andy's grandfather founded the Bank of East Asia, Hong Kong's largest independent Chinese Bank. Patti's grandfather founded Hang Seng, the second largest. Their union was a dynastic match. Now their combined Rolodexes heave with the addresses of London's most partytastic glitterati - Lady Victoria Hervey, Jemma and Jodie Kidd, Tamara Beckwith, Tim Jefferies and the above-mentioned Prince, not to mention obscure honorary Euro-royals such as Emmanuele Filiberto di Savoie (who calls himself the Prince of Venice, despite Italy having no monarchy). You get the idea.
Anyway, Chinese New Year is what the Wongs do, and Chinese New Year is why I've come to meet them, being ushered into a suite in this year's chosen party venue, London's well-to-do Great Eastern Hotel. It is 24 hours before the doorman downstairs will greet the first guests. "A Night Of Hedonism in 1920s Shanghai", states the invite. "Dress decadent".
Even off-duty, the Wongs are decked out in Bond Street finery - she in head-to-toe Jil Sander, he in Gucci, D&G and YSL. "I like to mix and match," says Andy, by which he means mixing flashy designer clothes with more flashy designer clothes. His shirt is unbuttoned to nipple-height, and a pirate's chest-worth of trinkets hangs round his neck.
Andy didn't really want to be interviewed and Patty really didn't want to be interviewed, on account of some veiled sniping previously directed towards them in the press. "Andy's as camp as Christmas", the Daily Mail reported one of their partygoers as saying, in a profile of the pair. "I bet they fight over make-up," another "friend" is reported to have said.
But such back-biting seems undeserved - the Wongs make a charming and good-looking couple. Same height, same build and same black Timotei hair, they arrange themselves on the plump sofa like a pair of chat-show hosts. Indeed, the dynamic between them soon reveals itself to be very much of the Richard and Judy variety. They chitchat over each other, with her wearing the trousers and him dropping clangers all over the place.
A man from the hotel - Simon - who has been in charge of realising the couple's requirements for tomorrow's event, fusses about fixing them Martinis, made to Andy's specifications: "Martin Miller's. Straight up. Two olives." (Martin Miller's gin is one of the several companies Andy has invested in).
Tomorrow's event is estimated to set them back pounds 50,000, with guests flying in from South Africa, America and all over Europe. The Wongs say all are personal friends. Has Andy ` spent today fielding calls from strangers trying to worm their way on to the guestlist?
"Not today," he says with Noel Coward diction. "For the last month! It's non-stop. There are so many celebrities who get their agents to call my office and say so-and-so wants to come and we say `NO! We don't know them!' I hear some people leave London because they're not invited," he adds. "They feel so embarrassed that they couldn't stay around with everyone saying `are you going?' I find it ridiculous."
Still, doing this every year... it's all very generous. "We've got so many friends all over the world, it's just nice to have them all in one room," says Andy. "Plus, we get many, many people who actually meet each other and become couples. Loads and loads, every year."
"Well," chips in Patti. "There's some break-ups also. When suddenly the guy sees someone else at the party and then..."
It soon transpires that enthusiasm for their shindigs is not evenly distributed between the Wongs: Andy has been beavering away for months, planning this and that, while Patti hadn't set foot in the hotel until today.
"I generate the ideas," says Andy, "and say to her `Patti, what do you think?' And she says `NO! Awful!'"
Patti rolls her eyes. "I'm like the well-worn brake pads," she says.
How long do their parties take to plan? When will they start having to think about next year's, for example?
"Oh God!" Patti puffs. "Don't talk to me about that. All he talks about is what he's going to do next year. He will get so excited in the middle of the night and say `Patti, you know what...'"
"...the theme next year will be..." says Andy.
"And I will be, like, you know what, Andy? I'm really tired. It's, like, three o'clock in the morning. And he will say `no, no, no - I've got all these ideas.' And he'll switch the lights on, get the notepad out and start making notes."
The Wongs have previously overseen a military-themed bash at The Imperial War Museum, recreated Beijing's Imperial Palace in Holland Park and, the year it opened, took advantage of the Millennium Dome. There's always a theme, which is not - repeat not - the same as fancy dress.
"It is never a fancy dress party," admonishes Andy. "You are supposed to look glamorous and attractive and beautiful. It's a dressy party and I really don't want people to come in casual clothes. Besides, fancy dress is that you have to... to... look ridiculous. Fancy dress is, you know, dress as a bear."
"It's not funny," says Patti. "He hates it."
It turns out the bear example may not have been chosen entirely at random. At the Wong's first parties, mindful of the fact they were supposed to be celebrating Chinese New Year, some guests showed up dressed as the relevant animal from the Chinese calendar. Andy was appalled.
"Actually, last year was designated the Year of the Monkey," he says. "And one of our very good friends..."
"I don't think you should mention this," says Patti.
"...actually bought a monkey. They had a trainer who had to go with the monkey, because obviously it can go wild and bite. But Patti was so bad, she started feeding it champagne..."
"No!" shrieks Patti. "I pretended! I didn't feed it champagne."
"You did!" says Andy. "I saw you. It's cruelty to animals! Call the RSPCA!"
And what animal is associated with 2005?
"Cock!" hoots Andy.
"Rooster," clarifies Patti.
The Wongs arrived in London in 1995. Both are Oxbridge educated - Andy at Cambridge, Patti at Oxford. Andy threw his first New Year's party while he was still an undergraduate. On graduating, he became a key member of the Far East division of Mercury Asset Management, although he packed that in a couple of years ago and now "invests in different situations". Patti is chairman of Sotheby's Asia. They were married in Ireland, where, in stark contrast to their Hello!-sized parties, the ceremony was attended by 11 people.
In 2003 they had to give the party-hosting a miss, on account of Patti giving birth to their daughter, Skye. And while Andy initially baulked at having to add a colourful nursery to their pounds 1.7m penthouse in Battersea - "minimalism doesn't go with children", he reported - he's since changed his tune.
I'd read that it was Andy and Patti's respective parents who suggested that their son and daughter would make a good match, but when I mention this Patti almost drops her Martini.
"Oh, no no," she says. "Never. Not from a girl's point of view. Andy's side did that."
Andy looks a bit crestfallen. "The two mothers thought that..."
"No!" says Patti. "I remember the very day... it's not true... your mother called..."
There follows a heated debate in Chinese, after which Patti reveals that, aged five, Andy and his friends used to bully her, prompting her mother to announce "God forbid my daughter ever marry anyone like that." Andy persists that "the mothers were plotting and planning" and that they thought they were "sort of suitable".
"It's so long ago," says Patti, firmly. "Let's not talk about the mistakes they made."
They agree that their parents wouldn't enjoy their parties. Their background is blue-chip, discreet, traditional Hong Kong Chinese. "I tell you," says Patti. "They used to loathe it. Both families are kind of anti-publicity. For them it's like, `Oh God, what are you doing?'"
Now they're a little more accepting. Though Andy and Patti say they still have to censor the photos.
"There's not enough dressing up these days," says Dame Shirley Bassey. "I collect 1920s jewellery and it's an era that I love." It's a little before midnight the following evening and the Wong's Chinese New Year celebrations are fully swinging. Dame Shirley, resplendent in pill hat and pearls, has been tucking into the champers and posing for photos. "Andy and Patti throw a wonderful party," she says. "You always meet such lovely people. I know I sing in front of huge audiences but, believe it or not, I'm quite shy." She has flown in from Monaco especially.
Mingling with her in the hotel atrium are Terence Conran, Elizabeth Jagger, someone who might be Caprice, Jerry Hall, Yoko Ono and John Lennon. Except... it's not John Lennon, it's son Sean, mysteriously dressed exactly like his dead dad circa Strawberry Fields. Prince Andrew has stayed away this time, but hundreds of other guests have risen to the 1920s challenge, albeit the girls more successfully than the boys. Still others have opted for a vague attempt at traditional Chinese dress. Leslie Ash has pushed a pair of chopsticks through her hair.
The Wongs, in matching Persil whites, meet and greet everyone. Patti is wearing a dress Vivienne Westwood has made for her, Andy a Gatsby-style suit. Both are wearing hats designed by swanky milliner Stephen Jones. Andy, quite unmistakably, is wearing foundation and blue eye shadow.
There are people on stilts, a horizontal, naked woman covered in sushi, an acrobat suspended from the ceiling by silk drapes and some quite spectacularly loud indoor fireworks.
But there's also lots drunk people braying, middle-age men letching after women half their age, cigarette butts all over the carpet and a couple having a stand-up row by the payphones.
Really, there are some things about Andy and Patti Wong's New Year party that aren't so unusual after all.