Matt Damon said in an interview that getting
John Malkovich was a big deal for the film, so much so that on the first take
John Malkovich did a very cartoonish and over the top performance at the end of which the whole crew applauded and praised him for how brilliant it was. At which point
Matt Damon looked
John Malkovich very confused,
John Malkovich seeing him looking confused leaned over and said "I'm a terrible actor."
Matt Damon said
John Malkovich was trying to show him that "if you get to that point where no one gives you a straight answer, it's dangerous"