"The Paperboy" pushes actors out of their comfort zones

(CBS/AP) "The Paperboy," a swampy slice of Southern gothic set in the 1960s that premiered at Cannes Film Festival today, pushes its stars - Zac Efron, Nicole Kidman and Matthew McConaughey -  out of their comfort zones.

Pictures: Cannes Film Festival 2012
Pictures: Fashion at Cannes Film Festival

Efron felt uncomfortable filming his revealing role, but he says that's the way he wanted it. The "High School Musical" actor has moved into decidedly grown-up territory with the film by "Precious" director Lee Daniels.

The 24-year-old Efron plays an aspiring writer helping his journalist brother (McConaughey) investigate a possible miscarriage of justice. Efron's Jack falls for Kidman's sparky but sultry femme fatale, who is in turn obsessed with a death row inmate (a supremely creepy John Cusack).

"I don't think I was supposed to feel comfortable," the 24-year-old actor told reporters in Cannes. "It's like life. This character is supposed to be learning the ways of the world, and that can be very uncomfortable. But it's also exciting."

Efron spends much of the film in his underpants, but says he didn't mind the scrutiny.

The film was also a departure for Cusack who sheds a lifetime of good guy roles to play the sweaty, sinister inmate, and loved every minute of it.

"I felt like I'd been let out of some cage," Cusack said.

Kidman stretches herself, playing a sexually adventurous woman drawn to danger. In one memorable scene she administers to Efron the traditional treatment for jellyfish sting -- urine.

"I'd been looking as an actor for something raw and something dangerous," Kidman said.

"I may be uncomfortable watching the movie. But that's my job -- it's my job to give over to something, not to censor it, not to put my own judgments of how I feel as Nicole playing the character. I am there to portray a truth.

"The Paperboy," adapted from a novel by Pete Dexter, has drawn mixed response in Cannes, where it is one of 22 films up for the Palme d'Or, to be awarded Sunday.

But the actors seem to have adored the experience. Efron said working with Kidman had been a dream.

"I've been in love with her for a long time -- since 'Moulin Rouge,'" Efron said. "It was the loveliest time in the world for me."