LOS ANGELES (Reuters) - Whenever a major Hollywood movie calls for its two main stars to go nude for large chunks of the film, then get up close and personal in steamy sex scenes, they usually exit stage left, running, protesting and quickly sending in body doubles.
Not Justin Timberlake and Mila Kunis. And not for their new romantic comedy, "Friends with Benefits," opening on Friday.
The pop singer-turned-actor, hot off acclaimed turns in "The Social Network" and "Bad Teacher," and the actress who is still trailing smoky sex appeal from "Black Swan," not only embraced the nudity and sex, they insisted on more of both.
The movie looks at what happens when two attractive but emotionally burned young professionals decide to embark on a casual sex-with-no-emotions relationship.
"We all workshopped it, which is unheard of, and they (the film's makers) also gave us a lot of leeway to make it our own," Timberlake told reporters at a recent news conference. "So we all worked on it, and it was through those rehearsals that we all re-polished it."
"I think we both wanted to make sure the script was in a place where we felt safe, and stood by it regardless," added Kunis. "And if the script hadn't got to that place, neither one of us would have done the film. So through all the rewrites we felt comfortable and believed in what we had."
The result is a film that, while it mines material similar to such recent comedies as "No Strings Attached" starring Natalie Portman and Ashton Kutcher, prides itself on being an "ultra-real, generational comedy," as Timberlake put it.
The two main characters' families -- Jenna Elfman plays his sister, Richard Jenkins his Alzheimer's-afflicted father, while Patricia Clarkson appears as Kunis' flaky mother -- help drive the plot. As does the often brutally honest comedy.
"A lot of the humor is a lot of us, and that's why we originally committed to it," said Timberlake. "When we first met, we found out..."
"We share the same sick sense of humor," Kunis said, finishing his thought and laughing. "It's exactly the same."
Timberlake joked that when he first found out Kunis would be naked in the movie, he "was like gross, eeew!...but I did it, because I'm a professional."
But there wasn't much kidding around when it came to getting in shape for the cameras.
Faced with a large number of bedroom scenes featuring extensive nudity, the stars approached their workout regimens somewhat differently. Timberlake said he likes to play basketball and golf, so he felt he was in pretty good shape.
"I mostly stopped drinking beer and eating sweets," he said.
For her part, Kunis said she doesn't play sports and, given that she was coming off her ballerina role in "Black Swan," she was actually putting on weight.
"I went to the gym," she said. "I had my trainer, and I did some sit-ups."
Ultimately, Kunis said she "suffered" for two weeks between the sheets, shooting the sex scenes. Timberlake said he "suffered for four."
To keep things fresh when shooting the bedroom scenes, the pair said they improvised "quite a bit" of the dialogue and situations.
"Daily there were some added 'What funny scenarios can we do?'" said Kunis. "The sneezing in the face scene was added on the day."
"We were actually going for laughs," Timberlake said. "That made us feel more comfortable as we were trying to come up with most awkward scenarios. So originally, there was no scene with me having to urinate while having sex. That whole scene just got added."
"It's very funny," added Kunis.
Editing by Bob Tourtellotte