Darden says he did a doubletake when he heard him utter those words. "I thought, 'What? Look who the f--- is talking. The nerve. Of all the people on the planet, this guy is telling me about my temper,'" he tells PEOPLE.
"I'm assuming it was him being more comical more than anything," he says. "But still…"
Back then, Darden was a 37-year-old prosecutor in the Los Angeles County District Attorney's Office, who tried Simpson along with lead prosecutor Marcia Clark on two counts of murder for the brutal slayings of his ex-wife, Nicole Brown, and her friend, Ron Goldman on June 12, 1994.
"I didn’t volunteer to work on the case," says Darden, who detailed his experiences from the sensational 1994-1995 murder trial – and the controversy that ensued after the jury's not guilty verdict in his bestselling 1996 book, In Contempt.
He has a new book, In Justice, about race and the judicial system, coming out later this year, he says.
Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.
While Simpson was acquitted of the murders in October 1995, Darden says, "I saw the evidence for myself. I believed he was guilty then and I still do now. I am a true believer that he is guilty."
A resurgence of interest in the Simpson trial reached a fever pitch in February with the debut of the hit FX series, American Crime Story: The People v. O.J. Simpson, which focused largely on the lives of the case's attorneys.
Darden says he did not it watch by choice, questioning its accuracy.
"I hate the idea that I did not have my hand in it," he says. "They took parts of my life and persona and put me in that movie without me having any control. If it was going to be done with a budget like that and the quality of actors they had, I could have made it better and given it parts of my voice.
"I turned 60 three weeks ago and my legacy is a memory of me. It's important to me because it's going to be important to my children and grandchildren."
Darden isn’t surprised that the nation is still enthralled with the Simpson murder trial.
"It’s the case that will never die," he says "People keep litigating it over and over."