She was the world's first supermodel, but Twiggy had never been on a catwalk until last year, she tells Viv Hardwick.

TWIGGY, the superstar shape of 1960s British fashion, didn't need the length of a camera shutter click to accept the role of George Bernard Shaw's whorehouse owner Kitty Warren.

The 1893 play, Mrs Warren's Profession, was banned until 1925. It deals with the murky world of a Victorian bordello boss financing her daughter's expensive Cambridge education.

Twiggy, married to actor Leigh Lawson, says of her controversial character: "I first met Peter Hall at the National Theatre, so it's always been a sort of dream to work with him. He rang me just before Christmas and offered me Mrs Warren on the tour and I can't think of many actresses who would turn that down.

"It's one of the great plays by one of the great playwrights directed by one of the great directors... and then I frightened myself to death by starting to read it and thought 'oh my god, what have I done?' Now we're up and running it's an absolute joy."

Each Thursday evening of the tour, the cast discusses the play with the audience and Twiggy, now 53, isn't all that surprised that the subject matter still shocks. With a daughter, Carly, the same age as the actress playing Vivie in Mrs Warren's profession, Twiggy admits she's often left thanking God their relationship isn't that estranged.

One discussion produced the response: "Well this couldn't happen today."

"There was somebody in the audience who said 'I choose to differ. I'm a lawyer and one of my clients is a high-class prostitute and she's had a daughter at university and is a wonderful middle-class young lady in her 20s and the mother is worried because the daughter doesn't know where the money comes from and at some point she's got to tell her'. We were all absolutely stunned. Isn't that amazing? We all thought it was a Victorian problem."

Twenty years ago Twiggy played Eliza Doolittle - "another wonderful Shaw woman" - in a TV version of Pygmalion and recognises the same streetfighter tendencies in her current role.

"I love Kitty," she says. "I've thrown my heart and soul into her. I do recognise the spirit of Eliza in Kitty. They are fighters who come from the wrong side of the tracks. It's that class thing again, the Victorian double standards."

The public was pretty hard on Twiggy, too, when she tried to break into the world of the chat show host in 2001 by joining the fateful line-up of Coleen Nolan and John Leslie to present This Morning on ITV. She lasted a month.

"I was doing my own chat show on a Sunday afternoon which nobody wrote about because it was doing fine," says Twiggy. "The problem was a clash between the woman who ran daytime TV and, as you know, Richard and Judy left because of her, and ironically enough, when I left, a few months later she went to Australia."

Twiggy claims that the This Morning episode didn't knock her confidence. Having a career on both sides of the Atlantic meant Twiggy took off for the US and did a play for six months. She admits that the Los Angeles atmosphere of "paranoid if you're not working and paranoid if you are" is best taken in small doses but enjoys a love affair with New York.

It's here she's hoping to catch a Long Island version of The Boyfriend being directed by Julie Andrews, who starred in the Broadway show back in 1954.

With the 1971 film, directed by Ken Russell, Twiggy won two Golden Globe Awards, for Most Promising Newcomer and Best Actress in a Musical/ Comedy.

She says: "I got to do the film because I saw it on stage and told Ken Russell about it. He'd had a lot of champagne at the time, but the next day he said 'what do you think?'. He upset a lot of purists because he changed everything, but it's a cult film now. The stage musical was too twee, that's why it couldn't be made as a film, but the cardboard characters work as a pastiche on stage. That's why Ken set it as this crummy touring company doing their tatty version of The Boyfriend which is hysterical. Sandy Wilson (the show's creator) was appalled, but you can't please all the people."

Twiggy's singing again on a CD called Midnight Blue, out on July 7. It's a little special because she has finally used some 1960s songs, which had been lost to a failed recording company, and added a few new ones including I Can't Talk To You, which has a backing singer called Carly Simon.

"I nearly died when we were having tea and she said 'I'll come in tomorrow and do some backing vocals'. It sends chills up my arm because you can hear her in the background."

Twiggy first became famous as a model in the Swinging Sixties. "The 1960s was an amazing time for new things to happen, certainly for London and England. I fell into it and I didn't say 'I live in the 1960s I'm going to do this'.

"I probably was the first supermodel and the first really working class model. They weren't from working class backgrounds. Most before me went off to become models so that they could meet a rich guy and settle down and have his babies. It wasn't a career choice in those days.

"In my day most little girls wanted to be film stars or ballet dancers. Now most little girls you talk to want to be supermodels or pop stars or just famous... which I find a bit unsettling. It would be nice to be famous for being good at something."

The girl who started as 5ft 6ins, 17-year-old Lesley Hornby from Neasden hasn't ruled out more flirtations with fashion. But she bursts out laughing when last year's appearance in the Gattinoni show in Milan was reported as her "parading the catwalk again".

"I had actually never gone on the catwalk in my life," she says. "In the 1960s, photographic models didn't do the catwalk.

"It was actually rather a snobby thing. If you were a top photographic model you didn't actually do fashion shows. That was for the lower echelons. Then in the 1980s, when people like Versace paid all those supermodels to come out and do the catwalk, it changed.

"Actually, my first time on the catwalk was bloody scary, great fun... but scary. There were hundreds of people there and all those photographers.

"I had a very beautiful dress on and bare feet because I was frightened of wobbling over with high heels on. It was very quiet in Milan and after about four steps some Italian guy shouted 'Twiggy I love you' and I was trying to be cool and moody, but I burst out laughing. They all clapped and cheered and it was really sweet. I'll do another if it comes up, but if you saw the list of things that comes through... At the moment my head, mind and soul are in this play and I'm loving it."

* Mrs Warren's Profession is at the Theatre Royal, Newcastle, from Tuesday, July 8 to Saturday, July 12. Box Office: 0870 905 5060