EXCLUSIVE: Oprah Winfrey on How the Dysfunctional Stories From Her Talk Show Help Inform 'Greenleaf'

Oprah Winfrey tells ET that the 25 years of dysfunctional stories heard on her former talk show are helping flesh out the characters on her new OWN series, Greenleaf.

"One of the things that informs me so much is all of the years of doing The Oprah Show," Winfrey told ET during a trip to the Greenleaf set in Atlanta. "It was like living in a life classroom where you're faced with every single dysfunction every single day. Being able to take some of those dysfunctional stories that people actually shared with me and our audience and be able to incorporate them into the lives of our characters is fantastic!"

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The series centers on disillusioned preacher Grace Greenleaf (Merle Dandridge), who has returned home to her estranged family after 20 years. As she re-enters the world of Calvary Fellowship World Ministries, the Memphis megachurch run by her powerful parents: Bishop James Greenleaf (Keith David) and Lady Mae Greenleaf (Lynn Whitfield), it becomes evident that things are not as virtuous as they seem and that the family's outward display of faith hides sin and misdeeds.

With infidelity, greed and abuse, Greenleaf has it all covered when it comes to dysfunction, and even though her former show prepared her for the undertaking, Winfrey admitted it's still a challenge.

With one scene in particular, Winfrey's character becomes unhinged with her onscreen sister, Whitfield

"That scene wasn't written when I came to set that day," she revealed. "I don't carry a lot of anger. I just don't. I don't even have it buried, so I have to dig so deep to bring it up, and the day we did that scene I had such a migraine headache from digging."

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Winfrey said the experience enlightened her about what some of the population must be struggling with on a daily basis.

"What I learned is, 'OMG, there are people walking around feeling this all the time!'" Winfrey said. "My gosh! They must be sick."

Fortunately, along with the dark subject matter there was also a few light moments for Winfrey in creating her potty-mouthed character, Aunt Mavis.

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"I wanted a real fro like I used to wear, and the fro was too big," Winfrey shared. "It was hard managing for framing the shot. They were like, 'We can't see around the fro!' And I didn't want a little fro, so we let that go and did the curly, wirey thing."

Watch the video below to hear Winfrey dish on the casting process for the show.