(Image Credit: Heidi Gutman/ABC News)

Mirror, mirror on the wall, who's the fairest of them all? To millions of moviegoers, it's Julia Roberts.

The "Pretty Woman" actress who also captivated viewers in her Oscar-winning role as Erin Brockovich is considered America's Sweetheart, but in her new role, she's far from sweet.

Roberts is playing the evil queen in "Mirror, Mirror," an all-new version of the classic Snow White fairy tale.

In an interview that aired today on "Good Morning America," Roberts told "GMA" anchor George Stephanopoulos all about her new role.

"My version of the evil queen is just a lunatic, which is fun," she said.

Lilly Collins plays Snow White, and Armie Hammer portrays Prince Charming, in the film directed by Tarsem Singh.

Roberts said Hammer is truly charming.

"He's six-foot five, good manners, sweet boy, always on time, knows his lines," she said. "And I think he brought a lot of great humor to that part."

Off screen, Roberts is a devoted mother of three, and wife to cinematographer Danny Moder.

The couple will celebrate their 10 th wedding anniversary this year.

"It's so good," she said of the milestone.

Roberts has her real-life love affair with Moder, but she now has a bit of a girl crush on singing sensation Adele, adding, "my oldest son has a crush on her too."

"She brings people in," Roberts said of the singer. "It's like her sharing is so open and genuine and seems to come from this really beautiful place that attracts us all to her."