LOS ANGELES - From the first time she saw "Hairspray" on Broadway, Nikki Blonsky was dying to play its plump, sparkling teen heroine, Tracy Turnblad.
At 16, Blonsky was too young when she auditioned for the stage role. A year later, the role of Tracy was hers, not on stage but in a big-screen adaptation of the musical that opens July 20.
Overnight, Blonsky went from teenager with only high school stage credits and a part-time job at an ice cream store to a lead role alongside John Travolta, Michelle Pfeiffer, Queen Latifah and Christopher Walken.
Blonsky - who had been singing since she was 3, starred in such productions as "Carmen" and "Kiss Me Kate" at her high school on New York's Long Island and seen countless other musicals on Broadway - formed a bond with Tracy unlike anything she had felt with other characters.
"I was just electrified by Tracy," Blonsky, now 18, said in an interview over breakfast at the Four Seasons Hotel. "We kind of have the same passion, the same drive, the theory of nothing will stop us and why can't anybody do anything they want to do.
"It was the first time I ever felt understood, if you will, by another person. By Tracy. I felt, oh my gosh, she gets me. Whoever wrote this gets me."
At 4 feet, 10 inches and well into plus sizes (she won't disclose her weight) Blonsky is not the usual ingenue. Her looks perfectly suit "Hairspray," which beneath its catchy tunes and peppy dance numbers carries a message for anyone who does not fit prevailing notions of beauty.
The musical version is based on John Waters' 1988 film starring Ricki Lake as tubby Tracy, a force of nature who leads the charge to integrate a 1960s TV dance show in Baltimore.
An outsider at school, Tracy is unfazed by naysayers, rushing home each day with best pal Penny Pingleton (Amanda Bynes) to watch the lithe dancers on "The Corny Collins Show" and dream of joining their ranks.
Tracy's mom, Edna Turnblad (Travolta, disguised in a fat suit and delivering an endearing performance as a sweet, bashful housewife), initially tells her daughter not to reach for impossible dreams. Her dad, joke-store owner Wilbur (Walken), urges Tracy on, and when Corny Collins (James Marsden) catches sight of her vibrant dance moves, she becomes a new darling on the show.
Before long, Tracy joins with record-shop owner Motormouth Maybelle (Latifah) in a fight to allow blacks and whites to dance together on air, battling the station's vile manager (Pfeiffer), who schemes to maintain the status quo.
Blonsky understood firsthand the opposition Tracy faced. She grew up in a supportive home with her father, a water-pollution official, her mother, a school aide, and younger brother.
At school, though, people were not always kind.
"I was constantly teased and made fun of and called every name in the book because I was short and curvaceous," Blonsky said. "My parents and my grandparents told me from a very young age, people make fun of you because they're insecure about themselves.
"So I came up with the motto of, well, if I can help people, this is the way I'm going to help. If they need to make fun of me to make themselves feel better, then they should feel better. Because frankly, I don't care if you make fun of me or not. It's not going to do anything to me."
With casting sessions in which they would evaluate more than 1,000 actresses across the United States, Canada, England and Australia, the filmmakers initially felt optimistic about finding the perfect Tracy, said producers Craig Zadan and Neil Meron. They later realized the search would be harder than expected.
"The requirements are so specific, so tight in terms of who could play her. You need someone who is a little unconventional in their weight, shall I say? Someone who is 17, 18, who can really sing great, dance great, act and carry a movie against all those movie stars," Zadan said. "How do you find somebody like that? Does that person actually exist in the world? After seeing all those girls, it was Nikki, and no runner-up. If we didn't find Nikki, we would have been in such terrible trouble. There was no backup."
Blonsky caught "Hairspray" director Adam Shankman's eye early on. She fit all the filmmakers' criteria - size, talent, charm and the fact that she was an unknown.
"She's very pretty, and she had extraordinary confidence. She seemed to love the way her body was and demonstrated all of Tracy's kind of unabashed zeal," Shankman said. "What you're seeing on that screen is who Nikki is. I didn't want anyone to have to act like Tracy."
From years of singing lessons and high school drama productions, Blonsky had the voice and acting chops when she sent in an audition tape and met with the film's casting directors in New York City.
What she couldn't do was dance. Blonsky had danced at parties in high school, but other than a brief time in ballet lessons when she was 5, she had no dance training.
Blonsky had gained confidence as she made it through round after round of callback sessions with the filmmakers. The now-or-never moment came when she went in for her dance audition in Baltimore.
"I credit it to the spirit of Baltimore. My feet just started moving, doing the Twist and the Mashed Potato. I didn't even know how," Blonsky said. "I was looking at my feet, going, `OK, Nikki, calm down. How are you doing this? How are you moving?' Tracy just took hold."
Five months after her first audition, Blonsky had the role.
Blonsky is reading scripts and has been on several auditions but has not yet lined up her next Hollywood job. She knows few lead roles come to short, curvaceous actresses, but she has resisted advice from people in Hollywood to change her appearance.
She had an unpleasant conversation with a prospective agent whose first words were: Lose some weight.
"At the end of the day, you don't have to go home with those people. You go home with yourself, and you make yourself happy. Those people don't make you happy," Blonsky said. "So if you just continue to take care of yourself, make sure your health is in check and everything is in check, then I think you're doing your job of being you, and just being OK."