THEATER : Petula’s Back! : Decades ago, she faded from American fame. Now she’s starring in ‘Blood Brothers.’ Where was she all those years? Everywhere.

“Usually you’re cast for the way you look and your general sort of aura, and with me it’s always been: Small, blond, nicely brought up,” says Petula Clark of her particular pigeonhole and of her initial reluctance to make her Broadway debut in the decidedly gritty role of Mrs. Johnstone in Willy Russell’s “Blood Brothers.”

Clark was brought into the cast in late 1993, along with former teen idol David Cassidy, to stimulate new interest in the dramatic musical’s moribund Broadway run. The change clicked with audiences and “Blood Brothers” quickly became a moneymaker. Clark and Cassidy remained on Broadway for 10 months before embarking in the touring production, the L.A. run of which opens Tuesday at the Wilshire Theatre.

While the musical still draws mixed reviews from critics, Clark’s against-type role, as a begrimed working-class Liverpool mother who gives up one of her twin sons to a rich family, has earned nothing but accolades for the singer--which begs the question: Where has she been all these years?

“Everywhere!” she says with a laugh, and she means it.

To Americans, Clark was a memorable but brief blip on our cultural screen. She arrived in the British Invasion days of 1965 with the No. 1 hit “Downtown.” That was followed by a run of indelible pop tunes including “Don’t Sleep in the Subway,” “A Sign of the Times,” “My Love” and “I Know a Place.” After starring in the films “Finian’s Rainbow” (1968) and “Goodbye, Mr. Chips” (1969), she drifted out of the mainstream.

But to Clark, her American success was an unexpected, and initially not entirely welcome, adjunct to a career that was already quite full. Unlike her youthful British Invasion compatriots, she was in her 30s when “Downtown” hit and had been performing on stage, radio, film and record since she was 8. In the ‘60s, she was living in Paris with her record-executive husband, Claude Wolff, and raising two small daughters. She was also coping with a French success so great that she surpassed Edith Piaf there and in other French-speaking nations, where Clark remains a major attraction.

“And then ‘Downtown’ happened by accident,” she said. “You don’t sit down and say, ‘I’m about to make a hit.’ It happened and whack , there it was at No. 1. in America. I was on tour doing a one-woman show in French-speaking Canada and these calls started coming through from Ed Sullivan. Claude said: ‘Ooo is thees Ed Sullivan?’ and I said, ‘Well I think he’s important, Claude.’

“And I was already totally booked. So, becoming popular here was an imposition. . . . Well, it was a wonderful, exciting thing to happen, but it really did complicate my life.”

When the hits slowed in America, she scarcely noticed. She simply appeared here less frequently while continuing to tour in Europe, North Africa and other locales.

When producer Bill Kenwright persuaded her to sign on with “Blood Brothers”--a mere month before she opened in it--Clark had to fly to London and New York for rehearsals around Paris concert dates she’d committed to on the weekends.

*

Comfortably curled in a chair in a Costa Mesa hotel suite a month ago, the day after opening the road production of “Blood Brothers” at the Orange County Performing Arts Center, Clark was casually attired and, wearing only light makeup, appeared an easy decade or two younger than her 62 years.

She took her time answering questions and admitted to never having been comfortable with interviews and the other formalities of stardom. Fitting then, that when asked to compare her childhood with David Cassidy’s teen-idol success, she opined that he’d had it much harder, because Cassidy had to endure Hollywood while she’d only had to put up with being bombed by the Nazis.

Clark did indeed sleep in the subways, and other underground spots, during German bombardments. And often she would sleep on the luggage racks of troop trains, traveling to the 500 performances she made during World War II for British troops. No matter what cameras or microphones she may have been in front of during the daytime, she said it was a curiously normalizing experience to be huddled in the dark shelters with other kids at night.

“We didn’t think being in the bomb shelters was weird as kids, because it was the only childhood we’d known. We thought it was rather fun, actually,” she recalled.

Her mother was Welsh, and much of her early childhood was spent in Wales.

“That’s probably where I get my musicality,” she said. “The Welsh are a bit like Italians, where they sing at the drop of a hat. My grandfather was a coal miner, and doing ‘Blood Brothers’ has brought back a lot of memories about being there, because my grandparents were very poor.

“But I lived in a kind of imaginary world. I was always talking to myself and walking on the street in the pouring rain singing. I was a bit weird, I think. My father heard me singing around the house and thought that I had a rather nice voice and he encouraged me. I started doing little concerts, which I enjoyed because I was really very shy, but I wasn’t shy when I was singing. I haven’t really changed that much. I kind of come to life when I sing.”

Her father became her manager. “He was a frustrated actor,” Clark recalled. “He ran away when he was a kid with a traveling theater and was dragged back by his parents, who thought that was shameful. He was a very handsome man who looked like Errol Flynn. In fact, he was once bitten in the leg by an Errol Flynn fan at some garden party. I think through me he was somehow living out his fantasy of being an actor. He was a good man, not a Svengali kind of person at all.”

In films, she often played the darling child waiting at home for the father at the front. Some sources have referred to the young Clark as a British Shirley Temple, but, she says, “it wasn’t anything nearly as glamorous as that. There was no big studio behind me, and there was none of that special grooming and schooling and that kind of thing. In fact, when the education inspector would come around the studio, they used to hide me in the cupboard and have this sort of midget person standing in for me.”

She did have the distinction of giving Alec Guinness his first screen kiss in “The Promoter” in 1952--”I was pretty shy but, God, he was really shy. It’s a wonder it ever got done”--and has fond memories of working with Peter Ustinov and Anthony Newley in “Vice Versa” in 1948. “To show you how long ago that was, it was the time when Olivier was directing ‘Hamlet’ in the same studio,” she said with a laugh.

She continued having British song hits through the ‘50s and early ‘60s. “At the time English entertainment was really dominated by America, so most of the songs I was singing were covers of American songs,” she said.

Then she found that a female French singer was having hits in that country with French covers of her covers of the American hits.

“I thought, ‘Good luck to her.’ What did I care? France was full of French people. But the record company kept asking me to go over there.”

So she did, and she became a huge hit singing in French, with her success spilling over into Italy, Germany, French-speaking Africa and other climes. She also met husband Wolff, who became her manager. She was an expatriate living in Paris by the time she became part of the British Invasion with the winter of 1965 success of “Downtown.” She still recorded in London, but says she “never got into all the hoo-hah” of the swinging London scene, though she did at times find herself rubbing shoulders with the Beatles, the Rolling Stones and other rockers.

She says she’s too enmeshed in the present to have much time for nostalgia, but she does have a marked preference for the way pop radio was then, when listeners could hear music ranging from hers to the Stones to Sinatra to Ramsey Lewis to Otis Redding on the same station.

“It was kind of like an explosion, and the music was all flying around all over the place. Now it’s a bit clinical the way things are done, very compartmentalized. I like the way it was because the people listening to it were fed all kinds of different things, which is rather nice and certainly more nourishing than listening to just jazz or just rap all day.”

She still has broad musical tastes, emboldened by a penchant for travel. Among the artists she admires are Michael McDonald, Annie Lennox, Lebanese singer Fairuz, Sufi singer Nusrat Fatah Ali Khan and Youssou N’Dour, whose music she discovered on a trip to Senegal years before Peter Gabriel brought the singer to international prominence.

She has a new album in the works, as well as a “Blood Brothers” cast album produced by George Martin. Other plans have been on hold because of the success of the musical. She expected it to occupy only a few months of her life, but it will be nearing two years when the touring production ends in May (and there’s talk of it being extended, she says).

Unlike the ‘60s success that broadsided her, Clark is at ease with the disruption “Blood Brothers” has caused in her life. Her children--two daughters and a son--are now grown and she can handle the long separations from her husband.

“There’s something to be said for it, actually, especially after 34 years of marriage,” she said with a laugh. “We manage to see each other from time to time. He’ll probably be joining me in San Francisco and Los Angeles. In some strange kind of way our marriage works.”

The couple moved to Geneva after the Paris riots of 1968 and still live there primarily, though Clark also maintains apartments in London and Miami.

She disdained going into particulars but said that balancing family life with her career hadn’t been without problems:

“I used to think I was doing it quite well, but in fact it’s not easy. I think I compromised so much in trying to do it all, trying to have it all. Somewhere along the line something gets neglected, and sometimes it was my family and sometimes it was my career. I have a lot of energy and you can just about do it, but you can’t do everything very well. So I’ve made some mistakes and there have been some bad times. The funny thing now is that I find that all those things are helping me, for instance in playing this role of Mrs. Johnstone.”

Though Clark had seen the London production of “Blood Brothers” and loved it, she said it never entered her mind that the downtrodden mother of nine was a role suited for her.

“I didn’t think I had it in me to play her. I have a great respect for this woman, Mrs. Johnstone, and for women who have to cope with very difficult circumstances I’ve never had. I didn’t want to misinterpret her, and it’s only now that I’ve been playing her for so long that I really feel I know her and can represent her onstage.”

Clark has the climactic song in the show, “Tell Me It’s Not True,” which she sings when she comes onstage to find her twin sons dead side by side. It’s a cold entrance, so she has to psych herself up nightly for the emotion the situation requires.

“I can’t always react to seeing these two actors lying on the stage because I’ve done it too many times now. So I think of some of the personal traumas, disappointments and sadnesses I’ve had or have seen. I think about this woman I’m playing, about all the women in the world trying to cope with the terrible lives that men have caused. I’m not talking about battered women, but about Yugoslavia and what I’ve seen in Africa, the struggle it is for them to take care of their children. Then I think about the huge sense of loneliness that I see all over the place. There is no shortage of things.

“Being perfectly practical about it, I remember seeing the most incredible interview with Jane Fonda where she said there was a private moment in her life when she was heartbroken about something, and she broke down and cried, and she looked in the mirror and said, ‘Ah, that’s what it looks like.’ You have to use everything,” Clark said.

After the turnaround success of “Blood Brothers,” she has been offered other Broadway roles but none yet to her liking. She doesn’t try to plan her career, she said, preferring to see where life takes her. Once she’s at an artistic destination, though, she feels obliged to give it all she can.

“The only thing that I’ve learned over the years is that if you do your best and give of yourself all the way through, you leave this wonderful trail behind you,” she said. “It’s just a small thing, unless you’re Einstein or someone, but it must have an effect on the rest of the world, little by little. I get very upset with myself when I do something that isn’t my best. It actually physically upsets me. I only met Laurence Olivier a few times, but I felt close to him, and there’s something he used to say, that he used to feel responsible for the weather not being good. And I’m a bit like that too.”

* “Blood Brothers” opens Tuesday at the Wilshire Theatre, 8440 Wilshire Blvd., Beverly Hills. Tuesday-Saturday, 8 p.m.; Sunday, 7 p.m.; Saturday-Sunday, 2 p.m. Ends March 26 . $20-$50. (213) 365-3500 or (714) 740-2000.