Oscar winner Jessica Chastain agreed to play Tammy Wynette in the new SHOWTIME/Paramount Network series "GEORGE & TAMMY" because after researching the country music icon, she felt so protective of her that she couldn't imagine giving the role to someone else. Michael Shannon accepted the George Jones part for many of the same reasons. After reading about him, Shannon found Jones to be "sweet and tortured and such an extreme combination of things."

"That always gives you the most room to explore as an actor," Shannon explains," when somebody is that complex."

Shannon, known for his Oscar-nominated roles in "Revolutionary Road" and "Nocturnal Animals, became frustrated when he learned that many people thought of country music's beloved "Possum" as dumb.

"I heard people say about George, 'Oh, he just had a voice like an angel, but boy was he stupid," Shannon recounted. "It really upset me, and I think it upset George, too. I think he was a very, very intelligent, deeply sensitive human being who dealt with a lot of adversity in his life and did the best he could. He was a savant."

Country music fans can watch Chastain and Shannon bring the intricacies and idiosyncrasies of Jones, Wynette, their music, and their complex love story back to life on Sunday night when the pair star in "GEORGE & TAMMY." The premiere episode of the six-part series will debut simultaneously on SHOWTIME and the Paramount Network behind "Yellowstone" on Sunday at 9 p.m. ET/PT. The remainder of the season will be available exclusively on SHOWTIME, with new episodes available on streaming and on-demand for all SHOWTIME as well as PARAMOUNT+ with SHOWTIME bundle subscribers on Fridays, before making its on-air debut on Sundays at 9 p.m. ET/PT. The series will also begin rolling out across additional Paramount+ markets outside the US and Canada.

"Jessica and Michael are truly extraordinary as Tammy and George, and their searing performances and undeniable chemistry bring to life the legendary relationship of the King and Queen of country music," said Chris McCarthy, President/CEO, Showtime and Paramount Media Networks, in a statement. "The creators and the entire cast have delivered a series with the subtlety, nuance, and complexity that are the hallmarks of the SHOWTIME brand and what our viewers deserve and demand."

Beyond reading about the singers, Chastain and Shannon got more familiar with them and their feelings about themselves and for each other through studying their music. The actors worked with celebrity voice and performance coach Ron Browning who helped them use the music to create more vulnerability in their characters.

"That's the first time I've ever experienced that," Chastain said. "I was so scared and so nervous. There were days that we'd be working on songs in different rooms, and I just was so terrified. It became a point where Mike was the person that was helping me overcome all of that. I think starting in that way created a bond to tell the story."

Chastain's favorite scene in the mini-series is the reenactment of the night Jones went to Wynette's house for dinner while she was still married to songwriter Don Chapel. Chapel and Wynette got into an argument and he called her a mean name. Jones was already in love with Wynette, told her in the moment, and the two left together.

"It really happened," Chastain said, who explained she talked to "the kids" and asked the question. "I was like, 'Well, you guys surely weren't there when he flipped the table.' They're like, 'Oh, no, no, we were. We saw it. The table flipped, and the chair went through the window. And she drove off with him.' I mean, to me, it's so, it's such an incredible leap of faith to do on both of their parts."

The scene was a challenge to act, Shannon said, because there are so many different versions of the story. He jokes that his "natural state is to try and not rip up the kitchen." He read accounts in different books and said the daughters who were present even had various versions of who said what.  

"You're kind of left scratching your head and thinking, 'Well, what was the truth? I don't know,'" Shannon said. "To that extent, it's a little bit liberating because you're not trying to recreate exactly what happened because that's just not even possible. Nobody even knows what that is. So even though you're recreating something that actually happened, you're also making something up at the same time."

He explained that by the end of filming, he and Chastain loved Jones and Wynette as a couple and "wanted to portray them how we felt they deserved to be portrayed."

The couple's daughter, Georgette Jones, gave the mini-series her stamp of approval and told "Vanity Fair" she thinks her parents would have been "pleased" by it, too.

"They really did a wonderful job putting so much into just six episodes," she said. "They just really were able to capture it."