As this Moon she rises higher

While she was shooting a scene for “Be Cool,” the line between reality and make-believe was blurred for Christina Milian. The actor-singer, who has a charming turn as aspiring chanteuse Linda Moon in the sequel to 1995’s “Get Shorty,” which opens Friday, had to remember she was making a movie while shooting a pivotal performance sequence with Aerosmith.

“I was really living in the moment like it was my own,” Milian says with a winning smile as she settles onto a chair in a restaurant near Culver City for lunch on a rainy February afternoon. “I feel like that’s still me. It’s not just a character. It’s not Linda Moon. When people see a moment like that, they know that I wasn’t acting.”

Indeed, the 23-year-old’s personable performance as Moon, a promising singer whom Shylock-cum-movie producer-cum-music industry maverick Chili Palmer (John Travolta) hopes to lead to superstardom, should only elevate her ever-increasing profile, one that includes several prominent movie roles and a recent Grammy nomination for “Dip It Low,” her sensuous breakthrough single as an R&B; singer.

In “Be Cool,” which reunites Travolta and “Pulp Fiction” costar Uma Thurman (as the wife of a record company executive), Milian’s Moon is a talented, struggling singer stuck in a bad management contract with ineffective music executives Nick Carr (Harvey Keitel) and Raji (Vince Vaughn).

Once Palmer muscles his way into Moon’s career, multiple plot turns ensue as Palmer wrestles with Carr, Raji and others for the rights to manage Moon’s career, while the rest of the cast, which includes Aerosmith’s Steven Tyler as himself, the Rock as Raji’s gay bodyguard and Cedric the Entertainer as a thuggish but upwardly mobile promoter, provide diversions.

“She’s like the ‘American Idol’ girl,” producer Michael Shamberg says of Moon. “But instead of getting off the bus and going to see Simon and Paula, [she] ended up with Vince Vaughn and the Rock.”

As the movie develops, Moon becomes a prized commodity for everyone even remotely connected to her. New to the music industry, Moon remains largely ignorant of the madness around her and enveloping her career. Portraying Moon’s innocence and naivete was not much of a stretch for Milian.

“Linda Moon and I are so similar in our personalities, who we are as far as our passion for music,” says Milian, dressed casually in a blue blazer, black T-shirt and jeans. “She knows what she wants, but it’s hard trying to make it through all these crazy people. I can relate to that.”

That’s because Milian’s first major exposure came when she appeared in 2000 with rap star Ja Rule, singing the chorus to his smash “Between Me and You” single. Milian seemingly was set to launch her career off the success of that song, but she ended up in, of all places, Sweden recording her debut album without the platinum production touch of Irv Gotti, the owner of the Inc Records, which releases albums from Ja Rule and R&B; star Ashanti, among others. The momentum created by “Between Me and You” evaporated.

When she returned to the United States and released the bubblegum single “AM to PM” in 2001, the response was less than enthusiastic. After all, she was best known for her collaboration with Ja Rule, a rapper with a thuggish bent.

“A lot of people expected a certain thing out of me when I first came out with Ja Rule,” Milian says. “But I still wanted to remain myself at that moment and do the type of music I was signed to do. It was a cool record, but it wasn’t what people expected, and I never got to put out an album [domestically].”

So in a very un-Linda Moon-like move, Milian took her career into her own hands and approached the executives at Island Def Jam, the label to which she was signed.

“When I finally realized how unhappy I was and that they weren’t listening, I cussed them all out -- and I gained their respect by doing that,” Milian says, laughing heartily. “I had to explain to them, ‘Do you know how serious I am about my career? This is not a joke to me. You’re embarrassing me right now.’ ”

Fortunately for her, Milian had an acting career on the side that was picking up steam. She landed a starring role in the 2003 comedy “Love Don’t Cost a Thing” and a supporting role in the 2004 action picture “Torque.”

Milian also decided to change her appearance and lightened her hair. “The best part of being a girl is dress-up,” she says. “You can change your look and look different whenever you want. People that I admired growing up were Janet Jackson and Madonna. They were constantly changing their image. So I [thought], ‘When did I like Janet Jackson the most?’ It was when she had her lightened hair.” And, like Jackson, Milian took it a step further, trading in the schoolgirl charm she favored in the video for “AM to PM” for a much racier, sexually charged image. One of her friends joked that the titillating video for “Dip It Low” was soft porn. Milian also appeared on the cover of King, a Maxim-inspired men’s magazine that is geared toward African Americans.

The results were satisfying, as her debut album, “It’s About Time,” sold 365,000 copies, and “Dip It Low,” which featured a version with rapper Fabolous, earned her a Grammy nomination in the best rap/sung collaboration category.

Interestingly, Milian’s music breakthrough had nothing to do with her landing the role of Moon. “She was shooting this stuff before her song and her record exploded,” says Stacey Sher, a “Be Cool” producer. “We didn’t cast her because of her recording career. We cast her because she had a great voice and also she was the best actress.”

Milian got an early start developing her acting and singing talents. She was born in New Jersey and raised in Waldorf, Md., a Washington suburb, and started auditioning with local talent agencies by age 9.

“I was very imaginative and very creative entertaining myself,” she says. “Television, listening to the radio, that’s what became my life. It inspired me to have fun, and it seemed like so much fun watching it, so I would try to convince my parents that I wanted to be inside the TV. It took some time to convince them.”

To help Milian pursue her acting and singing dreams, her mother moved with her to Los Angeles about 10 years ago. “Christine is what you could call a happy-go-lucky person,” says Milian’s mother, Carmen Milian, who manages her daughter’s musical and theatrical careers. (Christina Milian’s given name is Christine Flores. She changed it and adopted her mother’s maiden name in hopes of landing a wider range of acting roles.)

“If she ever complained about working, even as a young child, I would always remind her, if she’s complaining it’s because she’s actually doing it and she’s lucky she has a job,” her mother added. “There are people that would be begging to do what she’s doing now.”

In addition to “Be Cool,” Milian stars in the Tommy Lee Jones comedy “Man of the House,” which opened last weekend, and is working on her second album.

But it seems as though her role as Linda Moon will always hold a special significance. After all, the character is recognized at an award show for her music video at the conclusion of the film, a goal to which Milian aspires.

“I’ve never gotten to prepare to do an MTV Awards, so for me it was like, ‘OK, this is what it’s going to be like,’ ” Milian says with another big smile. “I didn’t have quite as big an audience, but it still gave me the feeling of what it is -- and I’ve wanted to experience that feeling my whole life.”