(Yahoo!) - For her first film, 'American Idol' winner Jordin Sparks had quite a co-star: Whitney Houston. And now that Sparkle has become the late singing legend's final performance, there's even more attention being put on the movie musical, which hits theaters on August 17.
"I get so overwhelmed because it's my first film, and for my first film to be so deep and heavy," Sparks, who plays the title character, says in the September issue of Redbook. "I got to work with one of my idols and sing with her, and she even played my mother. I don't know if anything will ever be as good as this. Sometimes I ask myself, 'Why did I deserve to have a part in a film like this?' I don't want this to come off crazy, but somebody said to me, 'It's like Whitney essentially passed the torch.' And to hear that, it's just nuts."
Houston, who was found unconscious in her bathtub on February 11 after ingesting a cocktail of drugs and alcohol, not only played Sparks' mother in the film — about three sisters who want to make it big as Motown-era singers — but she also acted like one to the young star. "She took on the mother role because my parents weren't there [during film production]," Sparks, 22, explains of Houston, who plays Emma, a failed singer who doesn't want her daughters to meet the same fate. "She was always asking: Did I feel comfortable? Did I need anything?"
And although her struggle with substance abuse was something that Houston kept private in her later years (she had maintained she was sober leading up to her death), it's a topic she would have been open about had she lived to promote "Sparkle," her first acting or singing gig since a disastrous 2010 world tour. "There are certainly some themes in the movie that everyone would have wanted to ask Whitney about like, 'Did you relate your own life to this part,' which I'm sure she would have answered honestly," says Sparks. "The cool thing about Whitney was that she was not scared to talk about or confront the things she had gone through."
Sparks' interview with Redbook wasn't all downbeat. The "Battlefield" singer also boasted about her drastic, yet slowly-paced 30-pound weight loss. "My whole journey has been about self-acceptance," she says. "There's no quick or magical way to lose weight. You just have to do it the natural way — diet and exercise and stick to it — and be able to do it at your own pace. Everyone has their own thing."
She's also enjoying her newfound love life with fellow pop star Jason Derulo, who she has been dating for the past year. "We both went through things that were tragic, and that brought us even closer together," Sparks says of her 23-year-old beau, who broke his neck during a rehearsal in January. "He had a near-death experience, and I lost someone. Priorities get in line when stuff like that happens. Family is what matters — and being with the people you love."