Geraldine Fitzgerald is an actress one readily associates with stage, screen and television. But music halls? "The first thing I wanted was to be in the music hall theater," she says. "I always kept this dream that I could do that." The realization of her dream is "Streetsongs," the one-woman musical me'lange she brings to the Smithsonian's Baird Auditorium Saturday at 8 p.m. and Sunday at 4:30 p.m.

Musical aspirations, says Fitzgerald, "have actually always been in me, because I was born in Dublin, Ireland, and the first theater I ever knew anything about was the pantomime and music hall theater."

It was not until 1968, however, with the film "Rachel, Rachel," that Fitzgerald, in her fifties, began to sing.

"I had a small part of a crazy preacher who gave services, sang hymns and was a flamboyant character. During one rehearsal, while I sang, the sound engineer kept coming up to Paul Newman, the director . . . they whispered . . . fingers twitched . . . and finally Paul came up to me and asked, 'Do you have to sing like that?' " She did, she said.

The name "Streetsongs," she says, comes from the tendency of people to take music hall songs home with them, to sing them "in the streets" and by themselves. "Music hall theater is very interesting, very upbeat. Even the saddest songs have a kind of exultation, because you feel that the person singing them has transcended that sadness."

Her show spans the spectrum of vaudeville-based music, and between the songs she tells the audience "what the songs are really about . . . how they came into being.

"At the end, there is a recollection of World War II when people used to sing in air raid shelters. I act the part of an air raid warden, and, with the illusion that they are in a shelter, the audience sings with me."