“When I saw Nikki’s first audition from the open call of hundreds of girls, my laptop started to glow,” says director Adam Shankman.

The “Hairspray” helmer wanted to cast an unknown for the part of Tracy Turnblad, the plump teen who dreams of appearing on a local TV dance show, in the movie version of the Broadway musical. He fell in love with newcomer Blonsky’s bubbly plus-size beauty and her friendly, high-energy vibe.

“I brought six girls to dance for me on the East Coast,” Shankman says. “She did pretty well, but there were other better dancers. Still, I liked the way she loved her body and really shook it and had a good time.”

Blonsky was 17 and dipping ice cream at the Cold Stone Creamery in Great Neck, N.Y., last year when she got news she’d landed the life-transforming role.

“I think Tracy is a one-in-a-lifetime type of character,” Blonsky says. “I want to make a mark in Hollywood where heavyset girls are cast on the size of our talent, not just the size of our hips.”

“In the audition, Nikki sort of tricked me,” Shankman affectionately remembers. “Maybe the (dance) combination was easy.” But once Blonsky relocated to L.A. to rehearse choreography and begin production, “We discovered she couldn’t dance at all basically. So she learned to dance on the movie. It’s about perseverance — and she earned it.”

Shankman believes that Blonsky will have a long career as a character actor.

“After I did ‘Bringing Down the House,’ people responded so well to Queen Latifah that studios started re-imagining parts originally thought of for males, for her,” he explains. “I think that might happen for Nikki. There’s going to be plenty of work for her. I would imagine she could also do really well in TV.”

In her second film, “Harold,” Nikki plays a sweet, quirky girl in love with the main character. Ally Sheedy and Cuba Gooding Jr. star.

Recent breakthrough: As Tracy Turnblad, ”she’s made me as much as I’ve made her,” says “Hairspray” helmer Adam Shankman.

Role model: “My mother and grandmother — they have guided and loved me so much. There’s nobody I want to be more like.”

What’s next: “I just finished my second film, ‘Harold’ with Cuba Gooding Jr. It’s a very fun comedy. I continue to follow my dreams and hope and pray to play more great roles.”