The scene was an unpretentious red-brick house in Maidenhead, Berkshire, on a hot August afternoon in 1981.
Apart from the top-floor flat, the building was divided into offices. The owner of the property, Samta Young Johnson, stood on the stairs, passing the time of day with a young solicitor, Howard McBrien, whose legal firm rented one of the floors in the building.
Mrs Johnson was a woman in her 70s, and a figure of absolute mystery, the subject of intense and feverish local gossip. Yet she blithely ignored every question about her past
Dressed carelessly and somewhat drably - "like the proverbial OAP", according to one of her neighbours - she nevertheless had an indefinable quality that compelled attention.
McBrien, who regarded her as "a great character", knew her to be fond of a glass or two of bubbly, a flutter on the gee-gees and the finest haute cuisine.
What he did not know was that this reclusive figure had once been one of the most legendary and celebrated stars of her age and the idol of millions of film fans and theatregoers.
American-born and flagrantly bisexual, in an era that scarcely accommodated such things, she had attracted men and women equally, becoming the mistress of four royal princes, and also of a future British Prime Minister.
She also inspired the passionate admiration of America's bisexual First Lady, Eleanor Roosevelt, as well as that of the world's most famous dramatist, George Bernard Shaw, who wrote one of his last plays for her.
On that August afternoon in the early Eighties, this tantalising figure, guarding her secrets, walked on up the stairs. Then suddenly she turned back to the young solicitor.
"By the way, Howard, you have children, don't you?"
"Yes, I have two boys," replied the puzzled McBrien.
"I thought so," she said, and continued her ascent to her flat.
McBrien was not to know that that day she would make her last will, one of the shortest and strangest documents on record, which she wrote out in her own handwriting, summoning a local draughtsman and a factory storeman to witness her signature.
When, three years later, Samta Young Johnson died from leukaemia at the age of 75, Howard McBrien was dumbfounded to discover that she had left him her house and her entire estate, valued at £162,000.
He was even more amazed to learn that his benefactress had been the fabulous Frances Day, Britain's original blonde bombshell and this country's first stage and screen sex symbol.
But she herself had lived in denial of that for almost 20 years.
What was it that caused a wealthy, famous and beautiful star to turn her back completely on her own past, abandoning even close friends such as the actor Sir John Mills and the ballet dancer Sir Frederick Ashton, and to deny her identity to the point of claiming that Frances Day had been her own mother?
This extraordinary enigma is resurrected by the release of a new double-CD to mark the centenary of her birth in December.
It features 49 of her money-spinning hit records - made between 1931 and 1958 - and reveals that she was a dazzlingly talented performer, oozing sex appeal that seems at least two decades ahead of its time, coming across as a forerunner of Marilyn Monroe.
Her story begins in the U.S. city of East Orange, New Jersey, where Frances Victoria Schenk, the daughter of an artist, Frank Schenk, of German-Jewish descent, was allegedly born on December 16, 1908.
Allegedly, because there is no birth certificate. Like almost everything in her life, even her parentage is shrouded in mystery, and rumours persisted for years that she was really the illegitimate daughter of Horace Dodge, the wildly eccentric millionaire American automobile pioneer.
At the age of 16, Frances was to be found dancing the Charleston in the notorious New York speakeasy of nightclub queen Texas Guinan, whose invariable greeting to her patrons was "Hello suckers!"
There, little Frankie Schenk was spotted by an ambitious Australian impresario, Beaumont Alexander, who thought she was "the ultimate in sex appeal".
He brought her to London, changed her name to Frances Day, transformed her into a platinum blonde, which was not her natural colour, and sent her to elocution lessons to eradicate all trace of her New Jersey accent.
Soon, he had masterminded her career as one of London's first exotic - and erotic - cabaret stars, dancing in West End nightclubs, where she created a sensation by performing in a G-string with only an ostrich fan for cover.
When she was 19, she married Beaumont Alexander, who was 18 years her senior, at London's Marylebone register office, but within three years they had separated, and she divorced him in 1938. There would be a legion of lovers - of both sexes - but she would never remarry.
In 1929, she first partnered the 21-year-old John Mills on stage.
"She was what in those days one called 'a knock-out'," Sir John recalled. "She was small with blonde hair and so well-endowed up front that, frankly, to put it in Army terms, she sported the largest pair of 'Bristols' it had ever been my pleasure to set eyes upon.
"She was devastatingly attractive, and I discovered later on, when I was in a show with her, that the men in the audience simply couldn't take their eyes off her."
Frances Day exploded into fully fledged stardom in the West End musical Out Of The Bottle, in 1932, aged 23. The following year, her extremely sexual performance as the notorious nightclub singer La MÙme ("The Shrimp") in Alexander Korda's movie The Girl From Maxim's rocketed her to the top of the film world, too.
Then, in 1934, came her biggest West End hit, Jill Darling!, in which her dancing partner was ballet legend Frederick (later Sir Frederick) Ashton. He would remember Day as "absolutely incandescent.
"The word 'star' in the theatrical sense might have been invented to describe her".
Frances Day was the 1930s equivalent of Marilyn Monroe: blonde, well-endowed, outrageously sexy and infinitely suggestive.
Her risquÈ songs were provocatively delivered with a breathy, squeaky gurgle, as in one of her most celebrated hits, Me And My Dog: "I'm just a little girl lost in a fog, Me and my dog, We're lost in a fog, Me and the dog are just wandering in a fog, Won't some kind gentleman see us home?"
The "little girl" in question is, of course, a prostitute, but Day delivered the number with so much charm and humour that not even the crustiest old dowager could have objected.
When she returned to the London stage in Beverley Nichols's 1937 revue, Floodlight, her co-star was John Mills, who observed: "Men adored her, but women disliked her. She became a permanent threat to their happy marriages from the moment the curtain went up."
More successful films followed, and further West End hits, including The Fleet's Lit Up in 1938, in which she stopped the show nightly with Cole Porter's song "It's De-Lovely", which became her signature tune.
Diana Morgan, who wrote much of the material for Day's 1939 revue, Black And Blue, remembered her wearing diamond and ruby bracelets from wrist to elbow.
Her lovers had included the Prince of Wales (later King Edward VIII and Duke of Windsor), his brother Prince George, their cousin, Lord Louis Mountbatten, Prince Bernhard of the Netherlands, Prince Bertil of Sweden, and Britain's Foreign Secretary and future Prime Minister, Anthony Eden.
It was not only men who fell under Day's androgynous, quicksilver spell.
After Frances's visit to the White House, America's bisexual First Lady, Eleanor Roosevelt, 23 years her senior, wrote to her: "I find I am quite unable to resist your extraordinary and tempestuous magnetism."
But as her fame grew, the more outlandish Day's behaviour became. Choreographer Wendy Toye once saw her arrive just as the curtain was going up.
"She simply threw off her white mink coat and went on stage in a pink and white lacy nightdress," she said.
"But her name above the title filled theatres, so managements were afraid to reprimand her in case she walked out of the show."
Although she was one of the first truly liberated showbusiness lesbians - Tallulah Bankhead and Marlene Dietrich were also involved in sexual interludes with her - Day's primary reputation was as a man-eater.
In 1941, she co-starred with the comedians Flanagan and Allen in the revue Black Vanities. When Frances arrived at one rehearsal looking decidedly crumpled, Bud Flanagan quipped: "Little Day, you've had a busy man."
It was in that production that she introduced the song A Pair Of Silver Wings as her personal tribute to the Royal Air Force.
Close friends knew, however, that she sang it for one man only: her fiancÈ, Squadron Leader Sam Johnson DFC: "Although they say he's just a crazy sort of guy, To me he means a million other things, For he's the one who taught this happy heart of mine to fly, He wears a pair of silver wings."
But during Day's run in the wartime West End musical Du Barry Was A Lady, Johnson was killed on active service.
She received the news with outward stoicism, but some said that she was never quite the same person again.
Her career went on. In 1944, she starred in another film, Fiddlers Three, and played the title role in Peter Pan on the London stage. But Diana Morgan felt that "the light that had made her a star was flickering and going out".
Yet her natural outrageousness remained. At an ENSA performance in Brussels, she sang "Thanks For All You've Done" directly to Field Marshal Montgomery of Alamein, and brought a blush to the bisexual hero's cheek when she "roguishly presented him with a pair of her drawers".
Noel Coward, who witnessed the incident, recorded that Monty "received both the sentiment and the drawers with dignified restraint".
After the war, there was a dramatic downswing in Day's popularity. In 1946, the West End musical Evangeline, of which she was both star and co-director, was booed by the gallery and closed after only 32 performances.
Her next London appearance, with Bonar Colleano in the comedy Separate Rooms, also flopped. By 1949, when she starred in the West End revue Latin Quarter, she was showing signs of increasingly erratic behaviour, causing the show to over-run by insisting on performing encores that the management had vetoed.
It was then, at the age of 41, that she began to pursue the legendary playwright George Bernard Shaw, who was 92.
"The ficklenesss of the women I love," wrote Shaw, "is only equalled by the infernal constancy of the women who love me."
To Day, he wrote: "You want to come down to flirt with me."
What she actually wanted was to get him to write a play for her, and in the end she succeeded. "She seduced him into it," says Diana Morgan.
But once the resulting play, Buoyant Billions, opened in London, Day transferred her attention from the aged author to a handsome 27-year-old actor in the cast, the bisexual Denholm Elliott, who married twice but ultimately died from Aids.
"Denholm was a bachelor and more interested in men at that time," says a friend. "Frankie didn't let that deter her in the slightest. She had the pants off him in no time."
With the West End closed to her on account of her prima donna-like antics, Day turned to television, appearing in the Fifties as a panellist on What's My Line?, in which she irritated the chairman, Eamonn Andrews, by her insistence on "special lighting".
In another Fifties radio game show, The Name's The Same, Frank Muir would never forget his first meeting with Day.
"From behind me," he recalled, "a hand came between my legs and grabbed my vitals. I turned round, considerably shocked, to find Frances Day looking up at me with her cute little pixie smile. 'Hello!' she said."
Day's behaviour gradually became stranger and stranger. In 1956, she elected to make a number of rock records, under the pseudonym Gale Warning. One of them, a version of Elvis Presley's Heartbreak Hotel, is included on the new CD, and is a disastrous error of judgment.
In 1957, Day's last lesbian lover, Moie Charles, the 46-year-old author of the film The Gentle Sex, was found gassed in her Chelsea flat. Her death was judged to be accidental, but it provided the final knock-out blow to Day's stability.
Her last television play, The Witching Hour, with Dennis Price and Thora Hird in 1958, showed that she was ageing rapidly.
Her final film was Michael Winner's Climb Up The Wall in 1960.
In 1965, she starred in one final West End play, The Gulls, opposite Bob Monkhouse.
Arriving for rehearsals on the back of a motorbike, in skin-tight black leather, sprayed with gold paint, she insisted on being billed as Frankie Day, and claimed that Frances had been her mother.
Monkhouse commented: "I think she must have had some sort of emotional experience. She has just entirely thrown out the past.
"Frances Day, as far a she is concerned, seems to have ceased to exist." When the run ended, she gave up her Mayfair home, retreated to Maidenhead and changed her name by deed poll to Samta Young Johnson. Local residents who recognized her as Day found that any reference to her past was ignored. In 1981, one of her Thirties recordings was reissued after featuring in the Donald Sutherland movie Eye Of The Needle, but EMI Records had no address to which to send the royaltie. When she died at the age of 75 in April of 1984 from chronic myeloid leukaemia, her brief will — leaving everything to Howard McBrien, who had known nothing of her glory days — proved to be an extraordinarily poignant document. It directed that "there be no notice or information of any kind of my death, except for and if a death certifica is obligatory. "Any persons, private or Press, you shall simply say that I am no longer at this address. "'Gone away. Destination unknown', and that is the truth". It was a sad and bewildering final curtain tothe dazzling career of one of the most glamorous show business legends of the 20th century.