JO Kennedy, who plays Jackie Mullens, the reluctant barmaid in the film "Starstruck" who wants to be a rock star at any cost, is riding a wave. Not the new wave of music that inspired the film, which is sort of a distaff, updated "Bye Bye Birdie," but the old-fashioned wave of good publicity that some feel could turn the perky 21-year-old Australian actress into a star.

Kennedy had been living in an empty warehouse, singing occasionally with a Melbourne band called Crashing Planes. "Starstruck" turned her into a star in Australia and reviews here have been generous to her. But, just as director Gillian Armstrong made "Starstruck" to avoid being cast as a women's director after the success of "My Brilliant Career," Kennedy has rejected every film offer she's received since "Starstruck" to avoid being cast as a rock ingenue.

"I finished 'Starstruck' two years ago, and since then I've basically been doing theater," she said on during a recent stopover in Washington. "I've got a band and stuff but I much prefer theater to rock 'n' roll. Rock 'n' roll is so tiring."

Kennedy, whose only previous acting experience had been as Pinocchio in children's theater, remembers how she got the call for "Starstruck" (which is currently pulling good houses at the Key Theatre in Georgetown). "I was 18, depressed, unemployed, poor. It was winter and a friend came around and said they were auditioning for this really big movie. I thought, why not, everyone wants to be a movie star, and I went to the audition. The next day I went back to see Gillian, realizing a bit more what the character was about. She was 11 stories up, and she said I want you to go down to the foyer and meet Ross O'Donovan another bright young unknown who ended up playing Kennedy's zany cousin/manager and pretend we won't give you an audition: come back and we won't let you in . . . you have to convince us you're good."

Kennedy and O'Donovan went out, stole a 50-foot fire hose and, dressed up in napkins, "threw the hose out the window, climbed out and hung there saying, 'Look, I can sing anywhere!' I just carried on and Gillian freaked, yelling, 'Get back in the window, what are you doing?' I jumped back in and she said, 'Can you sing?' I said sure, got on my knee and did a ballad. She said, 'How about rock 'n' roll?' So I jumped on the table, kicked her stuff everywhere, and sang. And I got the part."

"I'm glad I wasn't auditioning for a serious movie," Kennedy adds. "After 'Starstruck,' I realized how little I knew. In fact, I knew absolutely nothing." After two years of intensive training, she has finally signed to do a film "about a girl put into a mental institution, how she copes with it and how she has to adapt to life when she comes out. I would prefer to go on and do much more gutsier things, as well."

Kennedy, who grew up "in punk era of Johnny Rotten and the Banshees," points out that the music in "Starstruck" is not indicative of what's happening in Australia, or even of what she does. "I sang it as a character who's 18 years old and I made my voice higher and younger. The music is basically soft-pop but my friends and I are part of the underground, rather than part of the commercial scene. As far as music is concerned I'm more interested in doing it than promoting it. It was an interesting role but that's all."

The role did turn her into a pop star of sorts, with "Body and Soul" climbing to the top of the charts. "Suddenly I was famous in Australia but I'd never had time to think about what it would be like to be famous. And I didn't really like being famous. I'd never had any money, so I don't care if I don't have it anyway.

"The film was an enormous break and I pulled it off . . . just. But I look at my performance and I think it's just not deep enough; the script wasn't really deep. I just want to be so much better than that and whatever I do I'd prefer to be happy about it than care if it sells, so I'm prepared to take my time."

Kennedy recently received $15,000 to produce a play she's written and one suspects her career is in that medium ("in theater you can use ideas"). She had a few ideas about her role, too, recounting a few hardy arguments with Armstrong. "Never having done a film, I wasn't used to being told what to do and I had a totally different idea of what the character was. I wanted to play Jackie a lot more realistically, and Gillian wanted her to be a lot more glamorous floozy. I think you can see that clash in the film. A lot of my friends grew up in hotels and they were fat because they hated living there. They just ate and ate and ate and drank beer. And I really wanted to portray how hard it was to live in a pub and Gillian kept saying, 'Don't eat anymore biscuits, get that porridge out of your mouth.' "

She ballooned a bit for the film, but now Jo Kennedy is lean and anxious to prove that being "Starstruck" was more than a stroke of luck.