With an impressive box-office opening this past weekend, "Precious" proved to be worth all the critical acclaim and excitement brewing around it. The film features standout performances by pop star Mariah Carey, comedian Mo'nique and newcomer Gabourey Sidibe, who plays the title role. Sidibe credits director Lee Daniels for allowing the women to explore their characters.

"It was really, really cool. A lot of things that we said wasn't in the script, and so, like, we had free range," Sidibe said during her appearance on CBS' "Early Show" on Monday. "Mr. Daniels made sure we knew what the scene was about and that we can do whatever we felt like, and so it was really cool. And [Carey] was on her toes and I was on my toes, and it was almost like a fight, like a battle, because we are not friends really in this film at all. It was really cool."

While Carey transformed into a plain social worker for the flick, the usually light-hearted Mo'Nique became every child's worst nightmare. She plays Precious' mom, Mary, who shows no heart while her daughter battles familial abuse, rape, teenage pregnancy and the claustrophobic hopelessness that has invaded her life.

"[Mo'Nique] did such an amazing job," Sidibe said. "She is such a loving person. She is one of the most caring people I have ever met, and when the director said, 'Action,' she became this monster, and as soon as he said, 'Cut,' we would hug and laugh. We would love each other so much more because of the drama between Precious and Mary. It's amazing how those lines never got crossed."

Check out everything we've got on "Precious."

For breaking news, celebrity columns, humor and more — updated around the clock — visit MTVMoviesBlog.com.