With a voice so big — surprisingly big coming from her small frame — Christina Aguilera is practically built for a movie-musical. Welcome the new “Burlesque,” in which she plays an aspiring vocalist opposite Cher.

“I’m definitely used to coming from a world where I am able to express myself through song, through vocals, through writing lyrics, through poetry and having the time to focus on myself as an artist,” Aguilera says. “I find it much easier to express myself sometimes through song and through vocalizing my emotions. That’s why, at a young age when I had a very chaotic childhood, I would turn to song as my release out of that environment.”

Aguilera insists she relished the challenges of acting for the first time.

“Because it’s my first film, it’s a new thing for me, so I really tried to give myself wholeheartedly,” she says, though there was at least one unforeseen side effect of taking on the role of Ali, a young performer fresh off the bus from Iowa who works her way up at a Sunset Strip burlesque club.

“I would get very rambunctious,” she says of having to put her own personality aside to embody Ali. “I had a lot of pent-up energy, because I was being neglectful of myself, that when I wasn’t being Ali on camera I was really antsy.”

The show must go on

While she’s completely committed to her son, Max, Aguilera says she never considered putting her career on hold. “I think it would send the worst message possible to my child,” she says. “I think a lot of women, when they become parents, they think that that’s it for them, and they just shut themselves off completely to every other outlet that they were before they had children. And I think part of having kids is creating a good balance so that you can then inspire them to be their own individual and find what they’re passionate about and what goals they want to achieve in their lives. There’s a balance to everything, and he’s happy. And that’s the best thing about it.”