Perhaps there is no greater truth in life than this: Opposites attract. If you don’t believe me, just ask Paula Abdul. If you don’t believe her, Katherine Heigl and Gerard Butler’s new film, The Ugly Truth, might set you straight.

The film, directed by Robert Luketic (Legally Blonde, Monster-in-Law), is about what happens when Abby, an uptight TV producer (Heigl) is forced to work with the network’s newest contributor, Mike, a wild, testosterone-driven chauvinist (Butler). Since this is a romantic-comedy, you can assume that romance blooms through a series of comedic incidents. That’s what the genre dictates. But the film also delves into the hideous little secrets both sexes try to keep hidden from the other.

Butler says he was delighted to find a script that was “honest and frank about how we look at each other. What’s great about this movie is, it’s ridiculous and shocking, but men and women get it.”

The film also follows a recent trend in the genre toward a slightly more vulgar, in-your-face style, which both Luketic and Heigl were thrilled to embrace.

“There was this cloying, saccharine style of romantic comedy that people weren’t going to anymore,” the director begins, “perhaps because there was a lack of honesty and a sort of optimistic gloss that, as a society, I don’t think we all like that anymore. It’s not the ’50s. There’s now room to expand romance, explore other parts of it, more of how real people behave and more honesty.”

“I love raunchy humor,” Heigl continues eagerly. “I should probably try to be more sophisticated, but it’s just what makes me laugh the hardest and the most. I’m not terribly precious about that stuff unless you’re going really far ... and even then it’s funny.”

The cast and crew were committed to the comedy, but they seem just as enthused, if not more so, by the prospect of shedding light on the shrouded mysteries of the opposite sex. Butler, despite his reputation as a lothario (not dissimilar to the part he plays in the film), is deeply impassioned by how illuminating the film is.

“We never know, as guys, what women talk about when they go to the restroom, because they always go together,” Butler says. “And, likewise, women never really know how men really think. We all, at the end of the day, through our games, weaknesses and our flaws, are after the same thing. We all want a partner, we all want companionship.”

Surprisingly tender for a man whom the tabloids link to a new woman almost every week. So what advice do the stars have for the lovelorn and hopeful? For example, should a woman call a second time if the guy doesn’t call her back?

“No,” Heigl says empathically.

“Sure,” Butler shrugs.

“Would you really want a woman to call you not once but twice if you haven’t returned her phone call?” Heigl asks condescendingly and, seemingly, rhetorically.

“Yeah,” Butler nods. “I’m busy,” he adds with a laugh.

Rolling her eyes, Heigl smirks, “That’s exactly why you shouldn’t call him back.”

“That’s why I’m single” Butler crows.

“I’m so busy. Call me SIX times. Maybe I’ll get back to you,’” Heigl ribs.

“Listen, this is why it’s called The UGLY Truth,” Butler says. “The second you think the girl’s maybe not quite as keen, it’s like, ‘Oh, OK’ and when it’s right in front of you, it’s not quite as interesting.”

“It’s true,” Heigl nods.

“Please point out that she nodded when I said that!” Butler pleads.

“It’s true for women, too,” Heigl admits. “If you have a guy who’s just relentless and obviously so into it and puppy dog at your feet, it’s not as sexy and interesting as the guy who plays it a little cool.”

Speaking of counterfeiting emotions, one of Butler’s favorite scenes in the film involves Heigl, a pair of vibrating underwear and an homage to Meg Ryan’s infamous When Harry Met Sally scene. When asked about Heigl’s performance, which required 35 setups and tremendous effort from the actress, Butler whoops and claps.

“That scene will go down in the annals of history,” he declares. “But I knew it was fake. I get ’em all the time. I was like ‘I recognize that!’”

“Really?” Luketic asks, agog.

“Yeah,” Butler demurs. “I hate to admit it, but yeah.”