and here's the original quote from Q magazine:
Joni Mitchell: So there came Halloween, and I was walking down Hollywood
Boulevard. There were a lot of people out on the street wearing wigs and
paint and masks, and I was thinking, What can I do for a costume? Then a
black guy walked by me with a New York diddybop kind of step, and he said in
the most wonderful way, (croons) Lookin' good, sister, lookin' gooood. His
spirit was infectious and I thought, I'll go as him. I bought the make-up,
the wig, the sideburns, I went into a sleazy menswear and bought a sleazy
hat and a sleazy suit and that night I went to a Halloween party and nobody
knew it was me, nobody.