Writer/director Chinonye Chukwu suggested Alfre spend time with four of the eight female wardens running prisons in Ohio and the star decided to double down and chat with inmates on Death Row too.
But she had no idea she would be so affected by her time behind bars.
"Chinonye took me on a prison tour," she explains. "We were welcomed in all these prisons because they wanted to tell their story. I got to spend an hour with two condemned men deep in the bowels of a maximum security prison. I can't imagine they wanted to give what little time they had left telling this Hollywood person their story. So that was humbling and an honour that they opened up to me."
"I met people who work in the prison system. I just needed to see, breathe the same air... They are incarcerated themselves in a way, being inside. We ask these people to do the work that they don't want to do and they suffer PTSD equal to the troops that come back from deployment."
"We didn't shoot for a month after we did the prison tour. That shook me and I found myself spontaneously weeping for a month afterwards because I was shedding somebody else's tears, because the people who work in the prison system tend to keep all of these emotions in."