Chicago native L. Scott Caldwell is part of the very large and esteemed ensemble cast of “Mercy Street,” a six-part PBS Civil War drama miniseries debuting at 8 p.m. Sunday on WTTW-Channel 11.

Known as “Scotty,” the veteran actress shared her thoughts about playing Belinda, a recently freed former slave who is a servant in the wealthy Green family’s home in Alexandria, Virginia, in the early years of the Civil War.

Inspired by memoirs and letters from real-life doctors and nurse volunteers, the central focus of the PBS show is the Mansion House Hospital, an Alexandria hotel taken over from the Green family to serve as a medical facility caring for wounded Union and Confederate soldiers.

Will Smith greets his "Concussion" co-star L. Scott Caldwell at a premiere for the film. | Kevin Winter/Getty Images

Will Smith greets his “Concussion” co-star L. Scott Caldwell at a premiere for the film. | Kevin Winter/Getty Images

Caldwell, a 1988 Tony Award winner for the Broadway production of “Joe Turner’s Come and Gone,” said she was delighted the “Mercy Street” cast “was made up of a lot of theater people. I think we had something like five people in the cast who have Tony Awards,” including Donna Murphy, with whom she shared numerous scenes.

“Theater actors work in a different way than someone who is just a screen actor,” said Caldwell, explaining she most happily works with performers “who have worked their way up by putting their feet on the boards,” using the old term for stage acting. “It’s just a different approach to our craft.”

However, the key reason the former Chicagoan tackled the role of Belinda was “it was always something I’ve wanted to do — to play a slave. It’s been a fascination of mine for a very, very long time, because it’s the ultimate acting challenge, I think.” She had seen many films over the years that have included portrayals of slaves, “but I have not really appreciated much of what I’ve seen.”

Yet, there is one famous performance that has always resonated with Caldwell.

“Even as a child I was in love with Hattie McDaniel in ‘Gone With the Wind.’ That was never a popular thing to be in love with, because a lot of people criticized her playing that role, even when she did it in 1939. The NAACP tried to get her to not do it. Even a modern audience looks at that role and says she pretty much laid the groundwork for a very ugly stereotype, but I never felt that way.”

Caldwell went on to clarify her point of view. “I knew that [McDaniel] was a very smart, educated woman, who loved Shakespeare and who won elocution contests when she was a girl. So I knew that she was acting this role. She created all of that, in the context of the times.

“It was not a mistake that she received that Oscar [for best supporting actress, the first African-American to be both nominated and to win an Academy Award]. She was definitely acting.”

To create Belinda, Caldwell did quite a lot of research. “I listened to audio tapes that have been digitally restored — tapes of slaves actually speaking. I want to hear what that sounded like.”

As for the Virginia slave dialect she was trying to re-create, “I didn’t go as far as I could have gone, because you might not have been understood what I was saying. I did do what I could to fracture the language a little bit, but not go too far.”

Caldwell, known for her roles in the new movie “Concussion” and TV’s “Judging Amy,” “Southland” and “Lost,” where she played crash survivor Rose, loved the fact she again got to work with another former Chicagoan, Gary Cole, who plays the patriarch of the Green family her Belinda character works for in “Mercy Street.”

“This was like a reunion for us. He’s such an interesting actor. We previously worked together in the early ’90s on a TV movie called ‘The Switch.’ That also had a medical angle to it, though very different from ‘Mercy Street.’ In it I played a nurse who took care of his character after he was paralyzed in a motorcycle accident.”