Los Angeles —- Gwinnett County's nearly look-alike Nash sisters —- Jamia, 11, a co-star and singer in the Oscar-nominated "August Rush," and Olivia, 7 —- are in the hallway outside their family's hotel room at the Sheraton Universal, goofing around and having fun.

They sing and dance in full-blast kids' play. They sing songs they've collected on iPods and songs they've made up.

Every few seconds, one of the girls strikes an exaggerated pose and exclaims, "Superstar!"

Well, yes, that's the family goal.

Tonight at the 80th annual Academy Awards on ABC, elder sister Jamia will walk onto the entertainment world's grandest and most important stage and become Oscar's little big girl.

The youngest performer on the show, this sixth-grader from Buford will sing best song nominee "Raise It Up" from "August Rush" with the choir that sang with her in the film, the 21-member IMPACT Repertory Theatre of Harlem.

"I'm not nervous," Jamia says. "Not at all."

She steadfastly stuck by that remark all last week as she and her family, including dad and mom, James and Charlene Nash, trekked through a seemingly endless array of dress fittings, interviews, rehearsals, parties and pre-Oscar red carpet events.

Plus, since she's missed classes back home at Osborne Middle School, Jamia has had to squeeze in three-hour tutoring sessions.

One late night she's dressed in a floor-length, Single Girl silk gown, smiling and talking with supporting actress Oscar nominee Ruby Dee at a Black Enterprise pre-Academy Awards party, and by morning she's in a T-shirt and lounge pants contemplating mathematics.

She's already picked out her dress for tonight's red carpet: If alterations work out, expect to see her in a pink and bead embroidered Ella Zahlan couture dress with lace and a big pink bow.

Inside Oscar's hallowed Kodak Theatre for her official hour-long rehearsal on Friday, Jamia, wearing a jean jacket, pink top and jeans, stepped into the spotlight and belted out her first solo.

Watching from the theater seats was "August Rush" star Keri Russell, who will introduce the song performance on Sunday in a speech that dubs Jamia "amazing."

Backstage after rehearsals, Jamia said finally getting to test-run the Oscar stage made her feel great.

"I got excited just imagining all the billions of people watching," she said.

Oscar executives are considering adding Jamia into another unspecified segment of the show.

"Her voice is not only great because it is so powerful and rich, but Jamia speaks and sings the truth," says Jamal Joseph, the IMPACT choir conductor and one of three songwriters nominated for "Raise It Up." "She's like an old soul in a young body."

Jamia, who has a taste for Shirley Temples (she gets excited at dinner one night when the waiter advises the restaurant can provide her with one), is a seasoned performer.

She's been singing professionally since age 5, has performed at Harlem's legendary Apollo Theater and acted in kids shows and TV movies.

In "August Rush," which has earned nearly $53 million worldwide, she plays Hope, a young girl who befriends Freddie Highmore's character, a musically gifted and adopted boy searching for his real parents.

Four years ago, when she was 7, she was asked to sing at John Travolta's 50th birthday party in New Mexico. Jamia sang "Dancing in the Street" and "Wind Beneath My Wings." Travolta wept.

"I think the Oscar performance and the exposure to the millions of people who will tune in will take Jamia to the next level," says her father James Nash, who with two partners has formed Popular Entertainment Group to manage her career. "Despite everything Jamia has done so far, there is still a whole world we are looking to reach."

For her part, Jamia says she is very excited about performing at the Oscars. Some of the celebrities she can't wait to see: personal favorite "Hannah Montana" star Miley Cyrus, and Travolta.

She's been cucumber cool all week, playing with her sister or twirling in a formal dress and flashing a big smile for an "Access Hollywood" film crew or partying with TV kids at a Disney event.

"It's God working through me," she says of her lack of nerves. "If He wasn't in me, I would be shaking right now. But I have the confidence and the strength, and I have the courage and the right mind to recognize that I'm not nervous.

"I know it's hard for some people to understand," she continues. "I know how it can seem kind of weird. It's something in the heart you have to believe in. Fear and nervousness come from the mind. But the heart, that's where the real personality comes out."

She takes cues from both parents, who coach her on presenting herself well to the media and on performing. Both have been present wherever she went all last week.

In an off-site rehearsal Thursday at a Hollywood church, she frequently looked to her dad to catch his hand signals or to read his lips as he quietly coached her.

At other times he'd tell her not to look at him, but to go do her thing.

"I guard my babies," James Nash says of Jamia and Olivia, who's announced she, too, would like to perform. "I operate from a position of love. I have an intense desire to parent and nurture these babies and have my hand on them, but give them room to grow. The industry has an agenda. Someone might look to them as product. But it's up to Daddy to determine who we deal with and to make sure nothing, nothing happens to my children."

James lost his own father at age 6 and when Jamia was an infant, he'd hold her on his chest and sing to her.

"I used to sing to her that she would be the most powerful little girl in the world," he says.

His vision with Popular Entertainment Group is to take Jamia into multi-media: television, movies, pop music, books.

Jamia also looks ahead and sees a bright future.

"My goal is to become the biggest star on Earth and to stand on top and look down and see what I've done throughout my career and to die a happy person," she says. "Not a sad person who wasted their life throughout their whole career.

"You know, and they lost who they were."

ON AJC.COM: Oscars, at last!

Photos, stories from the Academy Awards.