It is a question she might well address to herself. Is the name Everage, or Barry Humphries, or Sir Les Patterson or Sandy Stone - or all of these? One problem is that Dame Edna suggests different answers at each performance, especially in the second act when he is on stage on his own for an hour and 20 minutes. And perhaps we will never know. Humphries himself seems to be having thoughts of mortality. "When I'm tired or run down I am aware that my father died at 68, and that I thought he was quite an old man," he said recently. He is 64. A close associate predicts: "After this run you may not see Dame Edna on stage again."
At a press launch in Jeffrey Archer's penthouse by the Thames, Dame Edna heaped ritual humiliation on anyone presumptuous enough to interrupt an impromptu 45-minute monologue. Had she had plastic surgery? asked a woman journalist who happened to be wearing a silk scarf. Everage replied in an audible whisper: "A scarf round the neck is so useful for women of our age, isn't it, my darling?"
Asked whether there was a sexual frisson between her and Jeffrey Archer, was it Everage or Humphries who replied, "Not a sexual frisson. More of a fiscal frisson"? Lord Archer and two associates put up pounds 521,000 to bankroll the new production. Lord Archer and Humphries were brought together 15 years ago by a mutual interest in art. Humphries is a collector and an expert, particularly of Victorian and Australian art - and a novelist and the author of a skillful and painful autobiography and a patron of new music. "He is much more serious than people would imagine, more like an Oxford don," says Lord Archer.
Melvyn Bragg found these matters of identity elusive when he interviewed Everage and Humphries in quick succession. "In his own house Barry was diffident, rather shy and very careful. In her dressing room Edna flaunts herself; she dares you and is reckless ... Barry was pretentious, a hopelessly deluded aesthetic wannabe. In every way a pitiful failure. It was fun; it was high risk; and it was creepy."
Barry Humphries was born in Melbourne on 17 February 1934, the oldest of four children. His father was a master builder who, says Humphries, indulged his every whim. Barry's relationship with his mother seems to have been a little more difficult. She shared the prejudices of suburban Melbourne at that time: anti-Semitism, stifling respectability and repressiveness. In More Please, his autobiography published in 1991, Humphries described how, as a small child, he had asked her if she loved him.
"Well," she replied, "naturally I love your father most of all, and then my mother and father, and after that you and your sister, just the same."
Humphries wrote: "It was clear from what she said that love had a strictly hierarchical structure, and was certainly not something that could be spontaneously experienced or bestowed."
Only a few years ago she told her son how distressed she was by complaints from fellow gentlewomen in Melbourne that Edna and Les Patterson besmirched the name of Australia. While still in her company, Humphries, trembling helplessly, impulsively called a radio talk show, and said: "The millions who laugh at Barry Humphries' shows should be ashamed of themselves. And I Happen To Know His Mother Agrees With Me." The voice was Edna's.
Parental disapproval must have been hard as Humphries grew up devotedly loyal to them. Peter O'Shaughnessy, the actor, director and historian, who was an early mentor, described him in his twenties still as "a street devil and home angel".
Ian Donaldson, a school friend, remarks on the contrast between Humphries then and his subsequent incarnations. "He was neither prankster nor clown," he wrote in a privately published book of tributes to commemorate Humphries' 60th birthday, "but a formidably learned, prodigiously clever young man, serious, ironical, allusive, and intense." He didn't care much for sport, though, sitting between the goalposts in soccer matches, or turning his back on the cricket field and knitting, or reading TS Eliot aloud.
Humphries' creativity blossomed when he got to university. In 1952 he earned local notoriety by mounting the Melbourne University Dada exhibition. Among his fans was a Melbourne schoolgirl named Germaine Greer, who was entranced by this Liszt-lookalike and loved to hear how her hero took his lunch into the pathology museum, where he could "munch away with relish as his eyes caressed the contours of the bottled foetuses, and all the other monstrosities and abortions that had been deemed worthy of pickling."
O'Shaughnessy, who is writing a book on the young Barry Humphries, remembers that he tried to turn Humphries' natural conservatism into a left-leaning bohemianism. He failed. Humphries left a shared loft at his father's insistence to get a proper job behind the record counter at EMI.
But his father could not smother the urge to perform. Humphries joined the Rep Company and, while on a bus tour, wrote a sketch on a tour bus called "The Olympic Hostess". (It was the time of Melbourne's Olympic Games.) Mrs Everage had been born. O'Shaughnessy recalls: "An Amazonian creature with sublime platitudes, pouting and simpering, haranguing and bludgeoning began to take shape."
O'Shaughnessy now says: "I lament the fact that this conservative man has played safe and sacrificed the lyrical child, like a clown in himself, the gauche, fumbling, stumbling, loveable, stammering creatures who were once so close to his then secret heart." One character he recalls in particular is Basil Clissold, a wretched, stammering, respectable young man. "Basil was Barry's alter ego," says O'Shaughnessy, "the Barry who had confided in me the twitches and faux pas that had marked his student-day encounters in the front seat of a car. It was the same tremulous Barry whom I had seen dragged away without a murmur of protest from the seamy Bohemia of an attic in Melbourne to a respectable job."
That hint of self-doubt is echoed by a long-time friend, CK Stead, who has written of Humphries' slump into uncertainty: "Of his four wives, I think of Auckland-born Rosalind as the heroic one. She worked so hard in those days to revive his confidence, to assure him he had been funny, had been admired."
A brief, early marriage to a dancer had faltered; Humphries and Rosalind, also a dancer, set sail for England in 1959, arriving, so he maintains, with precisely four old pence. But there were friends in London to help out. In the Sixties he bloomed, joining a Soho set, frequenting the Colony Rooms with Francis Bacon and Jeffrey Bernard. He wrote the marvellous Barry McKenzie strip in Private Eye where he enriched the English language with phrases like "technicolor yawn" and "pointing Percy at the porcelain". Barry McKenzie was more autobiographical than he realised. He now admits: "It was a therapeutic release for me, to write scornfully about the affectations and excesses of the 'poor old Poms' with whom I, Barry Humphries the artist, had failed to ingratiate myself."
He auditioned for Lionel Bart's Oliver and so impressed Bart that he wrote a song, "That's Your Funeral", especially for Humphries as the undertaker Mr Sowerberry. He acted for Joan Littlewood. And Rosalind bore him two daughters. But Dame Edna flopped at Peter Cook's Establishment Club where the audience found Humphries dressed up as a suburban housewife beyond the spirit of the time. It was well into the Seventies before Dame Edna really captured her British audience.
A Bohemian drinking style in Soho turned into alcoholism. Appearing in a Lionel Bart musical Maggie May, in which he was on stage only at the beginning and end, he would disappear on a spree for the remainder of the show. It was a recipe for disaster: "One night I appeared at the end of the show without make-up and in modern dress, when in fact I was meant to be a one-man band with cymbals and a mouth organ," he recalls.
Humphries left the theatre every night for a mental hospital where he was undergoing treatment for psychiatric problems, partly induced by alcohol and partly by serial infidelity. He was, he says now, "a dissolute, guilt- ridden, self-obsessed boozer".
Until 1972 that is, when he was found mugged, face-down in a parking lot. After years of waking in a cold sweat with irrational fears of impending doom, he went to Alcoholics Anonymous. By then he had lost Rosalind and forfeited the permanent company of his adored children. Next he married the surrealist painter Diane Millstead. That lasted nine years, and produced two sons. During those years Humphries consolidated his career as a gifted comic. But the marriage ended in bitterness, with Humphries losing nearly all he had in the settlement. He remains in contact with and proud of all his children. Now he is married, contentedly, to the actress Lizzie Spender, the daughter of the late poet Sir Stephen Spender.
Humphries can also be content that in Dame Edna he has given us one of the most potent and imaginative of comic creations. Unless, perhaps, like some of his earliest fans, he has not quite fulfilled his own expectations of himself.
Germaine Greer still voices a tinge of regret at the identification of Humphries with Dame Edna. She most fondly remembers him in 1958 as one of the tramps in Samuel Beckett's Waiting For Godot in Melbourne. "At his best, which I believe the English have never seen, Barry Humphries belongs in the company of the greatest clowns, men who can laugh in the teeth of the tragedy that is human life."
Spooky, isn't it, possums?