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There are actors who are known for wild, unhinged performances: Jared Leto, Jim Carrey, and Jack Nicholson, just to name a few (whose names all happen to start with “J”). But Brad Pitt isn’t one who immediately comes to mind, something director Terry Gilliam knew when he cast Pitt in 1995’s 12 Monkeys… in a role requiring just such a performance.

“I cast Bruce [Willis] and Brad completely opposite of what they normally did,” Gilliam recalls in the latest episode of PeopleTV’s Couch Surfing. “Bruce was always a motormouth…and Brad was always very laconic.”

But Pitt, according to Gilliam, “worked his ass off,” and arrived on set ready to be wild and unhinged. “This was his first day of filming,” Gilliam says, indicating the clip of Pitt going absolutely bonkers, running, jumping, and being very motormouthed indeed. “He just exploded on the set.” (Something must have stuck: though Pitt still isn’t known for craziness, he’s taken on other “motormouth” roles since, including in Inglourious Basterds and Guy Ritchie’s Snatch.)

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Meanwhile, Willis had to tone himself down, in more ways than one. Gilliam recalls telling the Die Hard star, “I don’t want Bruce Willis the movie star, I want Bruce Willis the actor,” and asking him to come to set “naked,” without his entourage and Hollywood-star accouterments.

“He did have his security guy, he did have his dietician. He had the truck with all the exercise equipment, and all that,” Gilliam says. “But in Bruce Willis terms, that was coming naked, basically.”

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