Twenty years have passed since the trial of NFL superstar O.J. Simpson was made for the alleged killing of his then wife Nicole Brown Simpson along with another man named Ron Goldman.

Now, the key witness to that case Kato Kaelin will reveal everything he knows on an interview set to air on Barbara Walters Presents American Scandals. According to The Inquisitr, Kaelin thinks that Simpson is guilty for the charges filed against him and that the jury made a mistake.

It was in the year 1995 when Kaelin became famous for being the witness on this case. During those times, he was a struggling actor and became a houseguest for Simpson. After the trial, the former football star was found not guilty of the charges bestowed upon him.

Barbara Walters then had a chance to talk to Kaelin after the trial without the any press involved and even then, he thought the jury made a huge mistake on their verdict. And now, he opens up again to Walters but this time with cameras for an exclusive interview. He said, "I remember that because you asked me off camera, you said, 'What do you think?' and I whispered into your ear, I said 'I think they made a mistake.'"

He made it clear that he wasn't a part of the jury and Simpson could've been convicted of those crimes. "I could only say what I knew and that's what I testified to, my opinion about his guilt is my opinion... In my opinion, yes, I think he's guilty. In hindsight, and everything, 20 years later, I think that O.J. Simpson is guilty," Kaelin added.

Kaelin also said the same thing during a Today Show appearance when he was asked about the case. But everything that the public needs to know about what happened 20 years ago would be revealed during Walters' show.