Scene in a television studio: a girl in a long pink shift, which catches at her ankles when she walks, picks hesitantly at a few bars on the piano, reluctantly gives up, and asks for a glass of something hot, maybe tea.
Her manager, looking like a thinner, less ebullient version of David Crosby, brings her a drink and she tells the audience sitting out there in the darkness of the television theatre that she must have picked up a cold in London, she always gets colds when she is in England; does everybody get colds when they go to America? Gives a nervous little giggle.
She resumes the song, unfolds it carefully like a love letter written on finest paper, pouring out its lines with a peculiar little sob in her voice, as if she cannot bear to let the words slip away. And they are deep, genuine words, about the lover who, "when he's gone, the bed's too big, the pan's too wide," which says it all so simply yet so fully.
Still in the same low key, she moves into the lyrics of Woodstock, and the line about the "bombers in the sky turning into butterflies above the nation," which is tremendous imagery, and then Willy; "he is my child, he is my father, I would be his lady all my life." No other contemporary songwriter could compose lyrics the equal of these in tenderness and innocence, a sweet combination.
She plucks at a couple of tunes on a dulcimer, which she has only been playing since February, and then picks up her guitar to sing Big Yellow Taxi, which gets great applause, of course, as does Clouds. She falters a bit on it, and cannot quite reach the pitch at times, but it is the final number and she has made it through all right.
Short pause while she stands timidly in the centre of the stage, looking vulnerable and dreamy, then fade-out.
Cut to the dressing room, and a typical dressing room scene, with a few friends, one or two press, a lot of record company representatives, and the usual well-known visitor.
In appearance, she seems rather severe in an attractive sort of way with her fine blonde hair scraped back from her tanned face, which has large bones around the cheeks and forehead, and a wide generous mouth. It's a pleasant, open face, that sits on top of a body whose seeming fragility inspires a feeling of instinctive protectiveness.
Joni Mitchell is not her real name. At Fort McCloud in Alberta, Canada, she is known as Roberta Joan Anderson, but in 1965 she got married to one Chuck Mitchell, a marriage dissolved about 12 months later. Her first album, SONG TO A SEAGULL, reflects the sadness of this marital split, and, indeed, the motions that have inspired many of her songs are always tangible, beating like veins near the surface of her work.
Willy, for instance, refers to her association with Graham Nash, now ended, while the impetus for writing For Free came from a clarinettist she saw playing on a London street — "nobody stopped to hear him, though he played so sweet and high," one line goes wistfully.
"There is a certain amount of my life in all my songs," she told me softly.
"They are honest and personal, and based on truth, but I exercise a writer's license to change details. Honesty is important to me. If I have any personal philosophy it is that I like the truth. I like to be straight with people, and them with me. But it is not easy to do this all the time, especially in this business where there is so much falsity."
Her first album was not released until late 1968, but she had been singing for five years then in clubs and bars, while her name was attracting public attention through other artists' interpretations of her songs: Judy Collins' version of Both Sides Now is probably the best example.
More recently too, Crosby, Stills, Nash and Young cut their interpretation of her lovely, floating song, Woodstock, whipping it up in the process into something fierce and pounding, far removed from the original in tone and execution.
"I liked their performance too, in its way," she said."They were seeing Woodstock from the point of view of the performers, while my version is concerned with the spirit of the festival. I never did actually get to Woodstock itself, you see, because the traffic jams to the site were nine miles long, so I sat in my New York hotel room and saw it on television."
If anyone has helped her, though, in popularizing her work it has been the cowboy rock and roll singer Tom Rush who, she said, had got her to leave Michigan, where she was doing the round of folk clubs, and securing her a gig at the Gaslight in New York.
This was not a total success, but Rush put out a version of her Urge For Going, after it had been turned down by Judy Collins, and this became a favourite on the club circuits, opening doors for her in consequence.
"Yes, he was the first to help. Until he played that and Circle Game nobody really wanted to know; they would time me when I went on as an opening act, so you can see that I have had to work my way up. It has all been very gradual. Tom helped me as well in that period because I was unsure about my writing, and didn't think it was very good. But there have been a lot of people who have been good to me."
Count among these David Crosby, who produced her first album. He has given her lots of hints on recording techniques, she says, and has captured in the studio her stage presence — "he helped to keep the music simple and basic."
"No-one paid much attention to folk music three years ago," she remarked quietly, "and the record companies wanted to change my music, so I had to wait until I was in a position so that I could play as I wanted."
The Judy Collins' album, WILD FLOWERS, which included some Mitchell compositions allowed her to bargain, and the subsequent albums had been made completely under her direction, even down to the sleeves.
All of the album covers she has painted herself, from the rather plain but expressively poignant self-portrait on CLOUDS to the stark simplicity of the sketch on LADIES OF THE CANYON.
But it is the songs within the covers that are important, and they are tender and sensitive, and as spare in construction as the line drawings on the sleeves.
Her great quality is her spirit of humanity: the compassion for the solitary clarinetist on the street corner, the unalloyed romanticism of Willy, or the comradely feelings for the half million gathered at Woodstock.
At the same time as being deeply emotional, though they manage to avoid the clingings of nostalgia, her work shows no signs of being mushy. Rather, it is built of sturdy bones, and in Big Yellow Taxi, for instance, shows humour, as she herself does ("Clean linen and funk" is my idea of a good life, she told me with a laugh).
For those who saw her on the Isle of Wight, or will be able to see the T.V. programme on BBC2, it was a brief glimpse of an American artist who bids fair to have the same impact in the Seventies on the popular musical consciousness that Dylan and Baez had in the Sixties. For those who miss her.
You don't know what you've got till it's gone.