Madeline Carroll and Callan McAuliffe star in "Flipped," an adaptation of the children's novel. The film, which is directed by Rob Reiner, is being released by Warner Bros. on August 6.

"The 'Flipped' cast brings together so many wonderful actors, some of whom I've worked with before, into a real ensemble as the families of these two kids," says Reiner. "It goes without saying, they're all brilliant. But I knew from the start that this movie would depend upon finding two young actors who could carry the Juli and Bryce story. They would be the heart of it."

Madeline Carroll as Juli

He was impressed with 13-year-old Madeline Carroll from the first time he saw her, opposite Kevin Costner in the comedy "Swing Vote." She was the first to read for the part of Juli Baker and, even after seeing other actresses, Reiner returned to his first instinct, remarking confidently to casting director Jane Jenkins, "We have our Juli."

Carroll approached her role with genuine understanding, describing Juli as "just a normal girl," but also one who is "very open-minded and creative, and not materialistic. She doesn't need the latest Barbie dolls or whatever, because she can have fun climbing a tree. She's a bit of a tomboy, and really independent, a girl who knows her own mind."

"She is definitely a tomboy," Reiner agrees. "And what I remember about girls like that is that they were so adorable but they didn't make a fuss about it, and they had all this energy and spunk. That's what Juli is all about, and Madeline knew it. There's nothing forced about her performance; it's never overdone, always perfect."

Callan McAuliffe stars as Bryce

The search for Juli's crush, Bryce Loski, was wider, ultimately reaching Australia, where the filmmakers found Callan McAuliffe, now 14. Reiner offers, "It was a difficult role to cast because, on top of everything else, we needed a young actor with a certain dreamy look. You have to believe that Juli fell for this guy the moment she saw him. Callan shows all his emotion in his face; you look at him and know what's going on inside, which is great because Bryce has a hard time expressing himself."

McAuliffe, who adopted an American accent for the role, liked the fact that Bryce is "a regular kid, and someone that people can relate to. It was an interesting role to play because Bryce has so many conflicting feelings and they keep changing."

As much as their nascent romance propels the story, Greisman notes, "It's partly what goes on with the adults in their lives that gives it context and direction. Seeing the choices their parents made and, consequently, the quality of their lives, is a factor for Juli and Bryce."