Matthew Modine, Lizzy Caplan on working with Robert De Niro in 'Zero Day'

JOJO WHILDEN/Netflix

Robert De Niro marks his first-ever leading TV role in the new thriller Zero Day.

Now streaming on Netflix, the series follows former President of the United States George Mullen, played by De Niro, who is called out of retirement in order to find out the source of a deadly cyberattack.

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Matthew Modine plays Speaker of the House Richard Dreyer in the show, and he told ABC Audio working with De Niro felt full circle.

“I was a teenager when I moved to New York City and wanted to be with those actors Robert De Niro, Al Pacino, Christopher Walken, Dustin Hoffman and all the incredible directors that grew up in a part of the fabric of New York City. So to be able to have the opportunity to work with him was really closing the loop,” Modine said. “He’s not just a great actor. He’s a great citizen. He’s a patriot.”

Lizzy Caplan, who stars as Congresswoman Alexandra Mullen, said playing De Niro’s daughter was a dream come true.

“When I signed on, only De Niro was attached, which is like, ‘OK, yeah, where do I sign?’ I’ll like, you know, change the toilet paper in his trailer. Like, what do I have to do to just, like, be on that set?” Caplan said.

To prepare for playing a politician, Modine said it was important to remember that they are all simply people.

“You have to remember that politicians are fleshy human beings that are subject to [having] bad opinions, to banking political errors and that they’re not above the law,” Modine said. “When they start acting like they’re above the law or that they’re better than the rest of us, that’s when we start getting problems.”