Playing Bernie Madoff may have been one of Richard Dreyfuss' greatest tests -- both as an actor and a human being.
In ABC's four-part miniseries, Madoff, the veteran actor expertly played the troubled investment banker, who pleaded guilty in 2009 to running the largest Ponzi scheme in U.S. history, stealing billions, and is serving a 150-year prison sentence.
Seeking Madoff's opinion or entertaining the thought never crossed Dreyfuss' mind. (In an email sent from prison to NBC News in February, Madoff said the ABC miniseries contained "numerous fiction[s] and absurd mischaracterization[s].")
"I never said to myself, 'I wonder what he'll think of this,'" the 68-year-old actor tells ET of Madoff. "I think if I had thought of it, I would have been ashamed of myself because he doesn't deserve it. He doesn't deserve any concern whatsoever."
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Nevertheless, the Oscar winner, much to the surprise of viewers, managed to make Madoff likable, to a degree.
"I knew that if he was going to be the most successful Ponzi scheme runners in history, he had to be someone that you trusted, that you felt comfortable with, that you enjoy him. So that was the reason why I did that," Dreyfuss explains.
"On one side, he was the perfect father and the perfect husband and the perfect legitimate businessman," Dreyfuss continues. "He was able to somehow compartmentalize in his head that the little girls whose grandparents came to him with all of their money, he was going to steal and ruin their lives. He did it for the worst of reasons."
With Madoff and the upcoming Fox series Shots Fired, which centers on a racially-charged shooting, Dreyfuss explained -- in a rather subtle way -- why he’s been leaning toward political projects as of late.
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"All of the films [and TV shows] I've done, one way or another reflect my principles or ethics," he says. "You may have to search a little, but they're there, so I'm totally comfortable doing Madoff and I'm comfortable doing Shots Fired."
Dreyfuss believes it's crucial to speak out about causes and political issues he feels strongly about, something he's done for decades.
"I think it's important that everybody does that -- not just actors. It's part of being a citizen," Dreyfuss says. "The more they speak and the more different opinions they hear, the better we all are."
Additional reporting by Stacy Lambe.
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