"Watching it happen again on television was enormously painful," Clark said in an exclusive interview with ET's Jennifer Peros. "It's killing me all over again."
Clark was the head prosecutor during Simpson's trial, and ended up taking a leave of absence from her job after the former NFL star was acquitted of murder, before retiring two years later. Clark went on to co-author a book about the case titled Without a Doubt.
Clark said that while Tuesday's debut of American Crime Story was "phenomenal," watching the events of the case unfold once again was like "reliving a nightmare."
"I think she is a genius," Clark gushed, adding that she feels it's "an honor" to be played by Paulson, whom she met with as the actress was wrapping up her work on the series.
"She's an amazing actress," the prosecutor said. "She surpassed anything I could have ever imagined. She's funny and so brilliant and she's a wonderful person."
Clark admitted, however, that she had to apologize to Paulson for one of her style choices during the highly-publicized murder trial.
"The first thing I said to her was sorry about that hair," recalled Clark -- who famously sported a curly perm during the televised proceedings -- with a laugh.
"She said, yeah, they had a series of wigs she had to wear," the prosecutor added. "So she didn't really have to [get a perm]. There's only so far you have to go."
Looking back, Clark is surprised that her appearance garnered so much attention, and says she’s happy that executive producer Ryan Murphy had "the guts" to take a look at the "sexism aspect" of how she was portrayed in the media.
"I mean, I'm a prosecutor. I'm not a model. I'm not an actress," she reflected. "I'm prosecuting a case, I'm a lawyer! No one had ever cared before … and suddenly everybody is talking about my hair and my makeup, it was mind-blowing. It was like living on another planet. And I have to say, no one until now has talked about that."
"I think the series actually makes an effort to acknowledge them and the ways in which that they were forgotten," Clark said. "This is an important series that's beautifully done, very compelling and I can't thank Ryan Murphy enough for what he's done here in terms of raising these issues in a very serious and compelling and very substantive way."
"But at the end of the day two people lost their lives in a brutal murder," she added. "So we have to remember that. We can't forget them again. Remember Ron and Nicole."
These days, Clark works in criminal defense, "helping people who can't afford to take care of their own," while also writing crime novels. Her latest book, Blood Defense, which draws on her legal experience to tell the story of a criminal defense lawyer with a "twisted kind of justice," hits shelves May 1.