Just when you thought that families portrayed on film couldn’t be more dysfunctional, the new Matthew McConaughey and Gina Gershon-starring dark comedy “Killer Joe” is ready for theatrical release. And its dark, seedy content has landed the film an NC-17 rating.

Directed by William Friedkin and based on Tracy Letts’s award-winning play, the southern gothic crime thriller centers on a broken, drug-dealing young man (Emilie Hirsch) who convinces his dad (Thomas Haden Church) and stepmom (Gershon) to join him in hiring corrupt small-town Texas sheriff Joe (McConaughey) to murder his mom in an effort to obtain her life insurance policy.

But as a financial “retainer,” they willingly give the sheriff their sweetly innocent 12-year-old sister/daughter Dottie (Juno Temple) as his sexual muse – and there’s no full frontal nudity or explicit innuendos spared.

But while the strict “no children under 17” rating might affect the film’s performance at the box office, some experts predict that it may give the film a cult following.

“While it may affect the ability to market a film, it brings a whole new cache of subversive marketing, and mainstream actors who give it legitimacy, credibility and raise it to a whole new level," box office analyst Paul Dergarabedian told the Associated Press.

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“Let’s wear it as a badge and keep it shined!” McConaughey said of the NC-17 rating for “Killer Joe.”

Still, despite his embrace of the rating, it took quite some convincing before the actor signed on to play a pedophile police man in what has been conceived as a humor-driven movie.

“I thought (the script) was gross. I put it down and threw it in the trash and wanted nothing to do with it. Then I took a long, hot shower,” he told FOX411’s Pop Tarts column. “But some other people close to me read it and their opinion was 180 degrees different from mine. They were laughing so I went back and read it. The first time I read it I got so sucked into this ugly world, I never could get above that to see any levity or humanity. I just thought it was icky, sticky, gross and I didn’t want to be in that company. Once I got the humor, it allowed me to see the story and the humanity.”

Only that’s not where the stomach-churning story ends. There are scenes involving fried chicken and Gina Gershon’s character that leave nothing to the imagination. Or in her words, “she puts it all out there” in a very animalistic way.

“I ate a lot. It was more physicality for me; I just wanted her walk to be some kind of alley cat but not very graceful. It was great, I could eat and eat and eat,” Gershon told us of her preparation for the part. “And I thought my family was screwed up…  It’s the darkest, darkest comedy I have ever seen but it’s hilarious. It’s very visceral.”

And even though “Killer Joe” paints a portrait of the trashiest of trash, redneck Texan family, McConaughey – a Texas native himself – assured us the locals who’ve seen the picture roared with laughter, and that the Lone Star state truly is a country in its own right.

“It’s a very independent state, an independent-minded state. It’s a state that has a lot of tradition and a lot of backbone, but at the same time it is a state that is not afraid to look forward and say ‘what is the definition of progress for tomorrow?’ That’s what I like Texas,” he added. “It’s a very resilient state. We mind our business and we like it that way.”

Films rated NC-17 are rarely commercial. Pedro Almodovar’s 2004 film “Bad Education” has the highest box-office tally of any NC-17 film with just over $5 million.

The Associated Press contributed to this report.