Jordin Sparks Jordin Sparks

American Idol winner Jordin Sparks mourned when her idol Whitney Houston died on Feb. 11, but paid tribute to her Sparkle co-star at Thursday's Essence Black Women in Hollywood luncheon in Beverly Hills, People reports.

"The first day she got [to the set] she's scolding me, and I'm thinking this is the best day ever," Sparks said. "She went from being this unreachable supernova pop star to my co-star, friend and someone who was like a mentor to me. It was a gift and an honor to play opposite Whitney Houston in the film."

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Sparkle, an upcoming remake of the 1976 film, stars Sparks as one of three sisters in a Mowtown-era singing group. Houston played their single mother. The film marks the American Idol champ's acting debut.

"When you see Sparkle, you will be so happy to see the joy that is on [Whitney's] face," Sparks added. "Every day started with Whitney saying, 'How are my babies doing? Are you guys good? God is good.' It translates on the screen."

Sparks also performed "Looking Into Your Heart," a Curtis Mayfield song that Houston had sung in the film.

Sparkle opens nationwide on Aug. 17.