Why Matthew McConaughey Likes Playing the Villain

In his new film Killer Joe, Matthew McConaughey takes on the dark role of "Joe Cooper," a crooked cop who is a hit-man on the side. Although the role strays from his typecast, McConaughey told ET that he enjoyed playing the film's villain.

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"It's fun because you don't follow anyone's rules but your own," he said. "You don't pander or placate any family, government, law, or anything. It's a real character that's an island unto himself...Joe's world is whatever's in his head, and that's how he deals with it. That's fun [to portray]."

Whether it's a twisted hit-man in Killer Joe, a passionate defense attorney in The Lincoln Lawyer, or a strip club manager in Magic Mike, McConaughey has seamlessly transitioned from starring in roles in romantic comedies to taking on more challenging roles that personally intrigue him.

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"I've been doing some characters lately that are arresting and sort of arrest me a little bit [and] challenge me in different ways," the 42-year-old Texas native said. "[They are] characters that, when I read them on the page, I don't feel like I could do it tomorrow."

McConaughey maintains that it is the challenge of having to do research and immerse himself in an unfamiliar character that ultimately excites and pleases him as an actor.

"I'm excited about who [the characters] could be but I feel like I know I gotta go do a lot of work and original creative character work to figure out who the guy is, and that's been really exciting for me in the last year."

VIDEO: Matthew McConaughey's Creepy 'Killer Joe'

Emile Hirsch, who plays the character who hires McConaughey's character to kill his mother, revealed that his attraction to work on the film was similar to his co-star's and resided mostly in his character's complexity.

"There [were] a lot of different things going on with the part, a lot of different emotions and things to play as an actor," said the 27-year-old Hirsch. "It's always fun to have a juicy role."

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Check out the full video above to hear what Juno Temple had to say about her sex scenes with Matthew McConaughey. Killer Joe, which premiered at the Venice Film Festival in September 2011, will be released in the U.S. on July 27.