Petula Clark had been playing Norma Desmond in the London production of "Sunset Boulevard" for about a year when she finally took the time to watch the movie that inspired the Andrew Lloyd Webber musical.
      "Trevor Nunn (the production's original director) didn't want me to see the movie when we were preparing for the show," Clark said. "So I hadn't seen the movie since it first came out. And back then, I was just a kid and honestly, I really didn't understand what was going on.
      "And I must confess, I had some very mixed feelings about the movie," she said, speaking by phone from San Francisco, where the "Sunset Boulevard" tour set up shop for a month of performances. "I had created my own conception of Norma Desmond, and by that time I was very close to that character. Then I see Gloria Swanson, and even though I know she was the original Norma, I found myself thinking, 'How dare she do that! Norma wouldn't act like that!'"
      Some of her many American fans might have difficulty imagining Petula Clark acting anything at all like Norma Desmond - an aging actress whose career ended when movies began talking, who now spends her days plotting her comeback to stardom with the help of Joe Gibbs, a gold- digging writer who turns up one day at her crumbling mansion just off "Sunset Boulevard."
      After all, Clark is best known here as one of the indelible voices of the 1960s, whose bright, cheery singing made classics of songs like "Downtown," "Don't Sleep in the Subway," "I Know a Place" and "This Is My Song." "Really, I wanted to be an actress since the age of 6, even though I wasn't really certain what that entailed at the time," she said. "But there wasn't much opportunity for child actors during the war. Since I could sing, I started doing that - singing for the troops, in church and at school."
      Clark made her singing debut on the BBC at the age of 8; four years, she appeared in her first film, "A Medal for the General." That role led to her being signed to a contract with the Arthur J. Rank Organization and roles in more than two dozen films produced by that company.
      "So I had two careers running along parallel lines," Clark said. "When I wasn't working on films, I was doing concerts. That is one reason why I love doing 'Sunset Boulevard,' because it's one of the few times I've been able to combine singing and acting."
      Clark is headlining the current touring production of "Sunset Boulevard," which comes to Tulsa for an eight-performance run beginning Tuesday at the Tulsa Performing Arts Center. The musical is part of Celebrity Attractions' 1999-2000 "Give Your Regards to Broadway" season.
      The possessiveness Clark now feels for Norma Desmond - a role that has been played by Patti LuPone, Glenn Close, Betty Buckley and Elaine Paige - is a quality it took her some time to develop.
      "Norma's not a terribly likeable character, you know," Clark said. "She's a difficult, deluded woman, who's been spoiled for ages and now is just totally out of touch with reality. She can be a monster. "That's why, the first time I saw the musical, I was rather turned off by it," she said. "I think of myself as a good audience - when I go to a show, I'm there to be entertained, to be caught up whatever is on the stage - and that just didn't happen. I couldn't feel anything for either Norma or Joe. If she's a monster, and he's just a gigolo, then there's no place for the characters to go."
      So Clark made the decision to make Norma more likeable - or at least more understandable - to audiences, by showing glimpses of the woman's softer side: her humor, her vulnerability.
      It was an approach made all the more challenging by the most notorious part of the original production: the elaborate, elephantine set. One of the more visually spectacular moments in the show was when the gigantic set of Norma's mansion rose to the ceiling to reveal another set.
      "That set - oh, yes, I know all about the pitfalls of that set," Clark said, laughing. "One time things went wrong and we found ourselves stuck in the air, suspended over this abyss. The characters were just physically and emotionally dwarfed by all that stuff on the stage."
      That was why Clark was reluctant to agree to headlining the touring production. A "Sunset Boulevard" was attempted in 1996-97, but was scrapped after only a few performances, because of the technical difficulties of moving the set in and out of theaters and around the country (it required more than 30 semi- trailers to transport and about a week to set up).
      But the director of the current touring production, Susan Schulman (whose Broadway credits include "The Secret Garden" and the 1997 revival of "The Sound of Music") wanted Clark as Norma.
      And her ideas about how to present this strange story about the way dreams can shatter were exactly what Clark wanted to hear.
      "I knew they wanted to create a production that would be easier to travel," Clark said. "But I didn't want to be a part of some watered-down version of the show - Andrew Lloyd Webber wouldn't stand for it, and I would not want to be in it.
      "But when I met with Susan and she started telling me what she wanted to do, I got quite excited about playing Norma again," she said. "Susan had never seen me in the role, but it was like she had read my mind."
      Schulman had seen the original stage production, but as she read the script in preparation to direct the touring production, she was surprised at how much of what she read she did not remember from the show.
      "That's exactly what I felt, the first time I saw the show - there was just so much to look at you had trouble focusing on what being said by the people on stage," Clark said. "Susan wanted to make sure this production told the story of these people as well as we could." One of Schulman's most revolutionary decisions was to play the idea of illusion that underpins the story - Norma's misbegotten belief that the world is waiting for her return to the silver screen; Joe convincing himself that he's something more than Norma's kept man as he tries to rewrite her screenplay; the efforts of Max the butler to maintain Norma's make-believe world of stardom - by making the set resemble a movie sound stage, with each individual set being created as if it were about to be filmed.
      "Some people may miss some of the glitz of the old set, but that's the only thing missing," Clark said. "But everything else is the same - the costumes, the jewelry, the songs, the orchestrations. It's not as elaborate a set, but it's still very beautiful."
      She laughed, then added, "Of course, Norma's environment has to be beautiful.