She's grown apart from Elton John and Liz Hurley. Now, an increasingly isolated Posh has turned to the Cruises - who are trying to turn her into Scientology Spice:
Victoria Beckham knows how it feels to be friendless: one of her formative memories is of being a social outcast at St Mary's High School in Cheshunt, Hertfordshire.
Most girls took the school bus, but she was chauffeured, Start-Rite shoes shining, in her father's Rolls-Royce.
At break time, she would be left standing in her neatly fastened Duffel on the edge of the playground, watching miserably as her classmates raced around.
They didn't want to know 'sticky Vicky' with her bad skin and posh family: she was never part of the in crowd.
Instead, she spent her time silently contemplating just how she was going to make them all very sorry indeed for ignoring her.
What sweet revenge, then, her new life must be. For she has just returned from a triumphant trip to America, where she took tea with Katie Holmes and baby Suri, followed by dinner with Tom Cruise, Katie and Victoria's 'new best friend' Jennifer Lopez and her husband Marc Anthony.
Victoria, who stayed at the Peninsula Hotel in Beverly Hills and appears to have subsisted on tropical fruit and Diet Coke, even acted as Katie's fashion stylist on a shoot for Harper's Bazaar just before she came home.
This stellar bit of mingling (about which she has boasted in several intercontinental phone calls) puts her, for the first time, within the orbit of the international A-list. It's the result of some pushy networking at the bizarre Cruise nuptials last month.
For it emerges that Victoria, undeterred by the sheer oddness of the spectacle, threw herself wholeheartedly into the festivities.
Wearing an extraordinary satellite dish hat and black cocktail dress, she seems to have treated the event as a giant promotional exercise.
She made sure she was twice introduced to J-Lo, even though the singer was at a loss as to who she was.
After she returned to Spain with her husband David, Posh then had her people call J-Lo's people, with the proposition that since she was going to be in Los Angeles hanging out with Tom and Katie, why didn't they get together.
She can be grabby and forward, says an old colleague. "It's that odd combination of being really quite insecure, but also pretty thick-skinned when it comes to getting what she wants."
There is a sense, though, that these transatlantic friendships are not quite as uncomplicated as they seem.
Could the Cruises be so very friendly because they are hoping Victoria will be the next high-profile convert to Scientology?
The couple have made J-Lo a friend of the religion and the get-together with Posh seems to have been celebrating the fact that Lopez, who was raised a Catholic, is said to be considering taking instruction and becoming a Scientologist.
David Miscavige, the cult's leader and Tom's best man, must be delighted. He is the man behind the movement's enthusiasm for celebrity converts.
And he and the Cruises know what a huge amount of influence the Beckhams have in Europe (identified by Scientologists as a key area for expansion with the opening of a new £10 million centre last year) and the Far East.
So, over dinner in Beverly Hills, Victoria is sure to have heard a lot of talk about L. Ron Hubbard, the science fiction writer who founded the movement, and his thoughts about the meaning of life.
But surely Victoria will not be swayed? She is not - yet - doing anything more than listening most politely to Tom and Katie and accepting Scientology books and pamphlets.
But some Beckham watchers believe she is so lonely that she is vulnerable to such 'love-bombing'.
Significantly, in recent months has been on more distant terms than previously with her very closest celebrity pal, Sir Elton John, who is godfather to her sons Brooklyn and Romeo.
Sir Elton is said to have rather tired of Posh, and his partner David Furnish is whispered to be fan of some of her alleged behaviour to the staff when the Beckhams use Elton's pink villa in Nice. Furnish, who has beautiful manners, has no time for anyone who is at all pushy or ungracious.
The relationship was strained by Elton's unguarded remarks at the height of the Rebecca Loos scandal, when he appeared to say was all Victoria's fault for leaving David alone in a hotel room in Madrid for six months.
"She and Elton are still friendly," says a friend, tactfully.
"It's just that they have seen very little of each other and not been in touch much as he has been busy touring."
But another adds: "They are barely in touch these days. Elton send the odd text or fax, and gets the odd text back." It's hardly the kind of behaviour you would expect of a close pal.
Nor is she bosom buddies any more with Elizabeth Hurley, who attended the Beckham boys' double Christening two years ago.
There is speculation about whether Miss Hurley is planning to ask Victoria to attend her wedding.
Victoria has also suffered a series of social reverses in fashion circles, where allegiances tend to be brittle and bitchy behaviour is the norm.
She is no longer close pals with Domenico Dolce and Stefano Gabbana, nor is she the most wanted client of several other high-profile designers, who can no longer be necessarily relied on for either freebies or a discount at their stores.
In recent months, with David busy in Madrid, it is notable she has had to resort to bringing along her hairdresser or make-up artist to social events.
When she went to Elton's wedding last year, it was her hairdresser, Ben, who, at 12.30am, told a rather tipsy Victoria that it was probably time to go home.
In fact, the only people who are truly inside the Beckhams' close circle are family members (her mother Jackie, father Tony and sister Louise, and David's mum Sandra) and employees (David's manager Terry Byrne and his wife Jenny, and Victoria's make-up girl, Marie Louise Featherstone).
"David and I don't have any mates," she moaned before their wedding. "We could have it in a postbox." And not much has changed.
Other Beckham allies are surprisingly few: Victoria is friendly with Lucy Rusedski (wife of tennis player Greg) and Tana Ramsay (wife of chef Gordon).
David is still close to Dave Gardner, the football agent, and his old Manchester United team mate Gary Neville.
"To be honest with you, over the years, he's been so busy with his football and playing for England, he didn't actually get much time to socialise," said Victoria this autumn.
"For the first time, we're getting a bit more time, so we've got to find him some mates."
So, what of the Cruise friendship? They were first spotted together two years ago, just as David was making his initial foray into the U.S. market with the launch of his football academy in Los Angeles.
It seems that the Creative Artists Agency, which also looks after Tom Cruise, effected an introduction.
After being dropped from the England team, Becks has identified America as the place where the next chapter of his career will unfold. A move to play for LA Galaxy is said to be likely when his contract with Real Madrid ends.
No wonder that Victoria showed such interest in the properties for sale neighbouring the Cruise home.
If Tom has Victoria in his sights as a possible Scientology convert, he has a long way to go.
Soon after their meeting, he gave her the book Assists For Injuries And Illnesses, and apparently she has told him she is very interested in its ideas about positive energy.
But according to sources in the U.S., so far he has failed to make any decisive impact on her spiritually (given that she confessed she's not finished a book in years, perhaps we should not be surprised.) She is, though, said to be open to spiritual possibilities.
Victoria - who was on the cover of Australian Harper's Bazaar last month - was the natural choice when Katie wanted the opinion of someone she could trust about her own cover for the American edition of the magazine, which was shot in New York earlier this month.
As Victoria has been heard telling Katie, she is about to become famous in America for the second time as a fashion expert.
The jeans she designed for Rock & Republic are well displayed in top store Fred Segal in Beverly Hills and were re-ordered three times by Kitsons in Los Angeles.
Katie obligingly wore the jeans on her honeymoon, which was a great publicity boost.
Victoria has parted company with Rock & Republic, and is finalising her own DVB denim range, which will go on sale alongside her sunglasses and handbags next year.
She will need all the celebrity help she can get to sell them in the U.S., where she remains largely an obscure figure.
Meanwhile, her manager Simon Fuller is attempting to sell a Pop Idol-type fashion show, featuring Victoria, to American TV.
The friendship with the Cruises, then, capitalises on a happy coincidence of aims and ambitions.
No wonder that Victoria, with her talent for social climbing, is taking such determined advantage of it. We can only wonder if a spiritual alliance is also on the cards.