For decades Dior insisted Liz Taylor's iconic dress was in their Paris vaults... In fact it was STASHED in a PLASTIC SUITCASE in the home of a window cleaner's daughter in Twickenham

Having been nominated for a 'Best Actress' Oscar in 1961, Elizabeth Taylor wasted no time in flying to Paris to commission a dress from Christian Dior for the ceremony.

For the previous three years, the 29-year-old starlet had narrowly missed out on the coveted gong, a losing streak largely attributed to her scandalous affair with, and subsequent marriage to, 1950s music idol Eddie Fisher who had been married to American sweetheart Debbie Reynolds when they met.

Finally declared the winner at the 33rd Academy Awards for her role in the film Butterfield 8, Taylor henceforth believed that the exquisite 'Soirée à Rio' evening gown she wore that night was her 'lucky charm'.

But what happened to it next is itself a saga worthy of any Hollywood movie. For while French fashion house Dior claimed for years that Taylor's Oscar dress was sitting in its Paris archive, an email to a London auction house last year finally revealed the astonishing truth about its whereabouts.

About to go under the hammer and expected to fetch up to £100,000, the Mail can now tell the story of how Taylor's gown ended up stashed away in the wardrobe of a window cleaner's daughter from London.

'I couldn't believe it when I took it out of the suitcase and saw it for the first time,' says Kerry Taylor of Kerry Taylor Auctions in London, who will auction the dress, which is embroidered with delicate flowers and insects, on December 12.

'It's one of the most important celebrity dresses to come on the market in recent times, and is in wonderful condition.

'It has an amazing story behind it and a water-tight provenance backed up by telegrams and family photographs.'

Believing the silk and taffeta creation brought her good fortune - it is thought Taylor chose the demure, scoop-necked style because of her 'scarlet woman' reputation - she carted it around the world for years as part of a vast trousseau of 40 suitcases.

But in the early 1970s, after deciding to clear out the wardrobe in the rooftop suite she and her fifth husband Richard Burton kept for years at London's Dorchester Hotel, it was among several items Taylor gave to her personal assistant, Anne Sanz.

Anne, who was married to Taylor and Burton's French chauffeur and minder, Gaston Sanz, was allowed to fill two large suitcases with various gowns by Dior and Karl Lagerfeld.

For the next half a century the items were carefully stored in a large plastic suitcase at the couple's flat in Hammersmith, West London. While Gaston, who was 18 years his wife's senior, died in 2003, Anne - who is still alive - has never spoken publicly about her friendship with Taylor.

But the couple's daughter, who was named Elizabeth after the Hollywood star, this week shared her memories exclusively with the Mail. 'The dresses were part of my childhood. I just always knew they were there,' she says.

So close were her mother and father to Taylor and Burton that when she was born in 1970, the stars were her godparents.

'She was the most engaging and loving godmother,' recalls Elizabeth who, as a young girl, travelled around the world with her parents and Taylor and Burton. 'And that carried on even after my father stopped working for them. She sent me little notes and gifts up until her death. I have very fond memories of her.'

As a child, Elizabeth was even occasionally allowed to try on the famous Oscar dress by her mother, but only if she promised to stand absolutely still.

'I used to think of it as a princess dress,' she says. 'It's absolutely exquisite and makes a wonderful rustling noise when it moves. But it's tiny and not something I could ever wear now.'

Fearing that the condition of the garment might deteriorate if they continued to store it at home, the family sought expert advice and were astonished to learn its value.

'It deserves to be seen and appreciated by people who appreciate the skill that goes into creating couture clothes,' adds Elizabeth. 'The dress is part of fashion history.'

The Sanz family's close relationship with Taylor and Burton stretches back to 1950s Paris, where Gaston, a decorated World War II hero who had fought under Charles de Gaulle, was working as a bodyguard for the fabulously wealthy Rothschild family.

He had been a crew member on the legendary French submarine, Rubis, which, after France fell to Nazi Germany, operated out of Dundee in Scotland, planting mines in the Norwegian fjords.

After the war, he trained in martial arts and became a French karate champion. Taylor, who met him at the Rothschilds' home, swiftly poached him to work for her, which he did for the next two-and-a-half decades.

While she became one of the most famous women on the planet, Gaston was one of her closest, most trusted employees, which was evident when tragedy struck in 1965.

In late February that year, when Gaston's son by his first, French wife died from a self-inflicted gunshot wound, Taylor leapt into action, chartering a private plane from Dublin where Burton was filming The Spy Who Came In From The Cold.

According to letters uncovered last year by biographer Kate Andersen Brower for her book Elizabeth Taylor: The Grit And Glamour Of An Icon, the actress flew to France and made the arrangements for the funeral. She also attended the inquest and visited Sanz's family in their Paris council flat.

The letters were written by Rock Brynner, son of actor Yul Brynner, who had been staying with Taylor and Burton in Dublin at the time.

'Gaston himself was on the brink of suicide, and now Elizabeth focused all her care upon him,' he wrote. 'She filled her purse with French francs, ready to bribe every official if necessary, to avoid a verdict of suicide, which would rule out a funeral in the Catholic ceremony.'

It was Elizabeth, too, who offered to look at the dead boy's face to see if he could have an open-casket funeral, and she walked with Sanz for the procession in the village and for the church ceremony and burial.

Landing in London afterwards, she was pictured clutching grieving Gaston's hand. He told reporters: 'In all that we have gone through, Miss Taylor has helped us by being such a human person. I want the world to know what a wonderful woman she is.'

Just a couple of years later, divorcé Gaston met his second wife, Anne, at a post-production party for the 1968 film Where Eagles Dare, which Burton had filmed with Clint Eastwood.

Born in London, Anne came from roots just as remarkable and as humble as Gaston's.

During World War II, her father fought in the Burma Campaign and, after being demobbed, worked as a window cleaner.

Her mother, a gas meter reader, served as a fire watcher on top of Battersea power station, looking out for German bombs.

'My mother was working for a bank which had lent money for the production, and she met my father there,' says Elizabeth.

'She was very striking, and is still very glamorous. It was a bit scandalous for my grandparents because he was almost the same age as them and divorced, but they all came to love each other dearly.'

The couple married in Paris in 1968 and, from then on, traversed the world with Taylor and Burton.

'Wherever Elizabeth and Richard travelled they were always accompanied by a huge entourage, moving from film set to film set and city to city,' explains Elizabeth. 'And wherever my dad went, my mum and I went. We were often in the suite next to theirs.'

The celebrity couple also spent time with Gaston's wider family in the South of France.

'They loved checking in on normal life,' adds Elizabeth.

Biographer Brower says the couple's close relationship with the Sanz family revealed another side to them. 'Elizabeth was drawn to regular people who weren't intimidated by her,' she says. 'She was looking for something more grounded in her life because she'd been a child star and had never really had that.'

Off screen, Taylor was a devoted mother and Anne was occasionally asked to mind the couple's five children - Burton's daughter, Kate, from his first marriage; Michael and Christopher, Taylor's sons by second husband, Michael Wilding; Liza, her daughter with theatre impresario Mike Todd, who died in a plane crash in 1958; and Maria, the daughter she and Burton adopted in 1964.

'My parents had a close relationship with their children as well because my mum and dad were always there and for my dad, having lost a son, having other children around meant a lot to him,' says Elizabeth, who was much younger than the Taylor-Burton brood.

The Sanz family travelled to Paris, Mexico, Italy and Gstaad in Switzerland, where the couple kept several homes, including one just to house Taylor's vast clothing collection.

They sailed around the Adriatic on their private yacht, the Kalizma. A photograph taken off the coast of what was then Yugoslavia shows Taylor kissing toddler Elizabeth, who is in her mother's arms.

In his diaries, Burton wrote that 'Gaston works like a dog. He charges around, shopping, answering telephones, emptying Thermoses, preparing salad, defleaing the dogs and watching us wherever we go, and all with the greatest humour. He really is indispensable'.

Anne, who helped Taylor with her packing and once knitted Burton a jumper which he wore until it fell apart at the seams, was also much loved by the stars. Taylor even gave her a white cocktail dress and bolero for her wedding to Gaston. It is also up for auction, with an estimate price of £400-600.

Among the other dresses given to Anne is a blue silk crepe dress by Christian Dior, which Taylor famously wore to the June 1968 wedding of the daughter of the Queen Mother's racehorse trainer, Peter Cazalet. It is expected to sell for between £10,000-£15,000. A 1967 Karl Lagerfeld kaftan Taylor wore for the film Boom! has been given an estimate of £1,000-£1,500.

When Taylor and Burton divorced for the second time in 1976, both stars wanted Gaston to work for them. Unable to choose, he diplomatically announced he and Anne were going to settle in London so that Elizabeth could attend school. Gaston took a desk job as a finance officer at what was then West London Hospital in Hammersmith.

But the families kept in touch, with Taylor and Burton sending telegrams on birthdays and at Christmas. Throughout her childhood, Elizabeth received regular letters and gifts, including an inscribed Tiffany watch from Taylor when she turned 18.

After Burton died, aged 58, in 1984, Taylor invited the Sanz family to a memorial dinner at The Dorchester in London. 'There were so many famous faces and all Richard's siblings came as well,' Elizabeth recalls. 'I was 14 and I remember I sat next to actor Edward Fox, who was charming.'

For the rest of his life, Gaston refused to speak about his time at the heart of the Taylor-Burton entourage, despite approaches from journalists and biographers.

'My dad was trusted and would never have betrayed that,' says his daughter. 'They supported each other through some difficult personal stuff.'

In 2003, the French government awarded Gaston the Legion d'Honneur, France's highest award, for his wartime service. He died in October of the same year.

When Elizabeth Taylor died in 2011, aged 79, Elizabeth and Anne were among 400 guests invited to her memorial in Los Angeles, mingling with stars including Michael Caine and Elton John. But what meant the most, says Elizabeth, was seeing Taylor's children again.

'It was so moving to hear some of their recollections about my parents, especially my dad,' she says.

While Anne has vowed never to speak about her time with the famous couple, the forthcoming sale of the 'Soirée à Rio' dress has given a precious and moving behind-the-scenes glimpse of the lives of two of Hollywood's most legendary stars.

Auctioneer Kerry Taylor says: 'It's such an important dress and not just in terms of Oscar history. I'd love for it go back to America so that it can be in the country where it was first worn.'

The other possibility, of course, is that Dior will quietly bid for it. The fashion house did not respond to requests for a comment this week.

'Who knows if they'll buy it,' says Ms Taylor. 'It's the funniest situation. They think they've got it in Paris, but we know they haven't. We have it right here.'