The hashtag "#DidOJConfess" trended on Twitter throughout the broadcast.
In the special, Simpson says that he had become angry with Nicole in the weeks before the murders because of her alleged drug use and relationship with Faye Resnick, who he refers to as a 'hooker' and 'call girl.'
Things reached a boiling point on the day of the murder when Simpson claims he was told by a doctor that Resnick and possibly even Nicole would be going to rehab while at a dance recital for his daughter Sydney.
That night, he made the decision to go confront Nicole about this at her home, arriving with a friend he calls 'Charlie.'
Things got heated when he saw a man he did not recognize arriving to meet Nicole, Ron Goldman.
Then, while he and Nicole were yelling at one another, his ex fell over says Simpson, at which point Goldman threatened to fight him with karate.
That is when he claims Charlie came up to him while holding a knife that he either got from Nicole's home or Simpson's Bronco.
Simpson says that is when he blacked out and when he came to was covered in blood, so he quickly fled the scene with 'Charlie,' leaving his two children alone in the side the house while their dead mother lay fatally stabbed outside the door to her home.
The segment begins by pointing out that though what the football player says is hypothetical, it is 'tantamount to a confession.'
Regan revealed in a clip that has been cut from the upcoming Fox special that Simpson confessed to the murders via his lawyer.
'Actually I received a phone call from an attorney who said OJ is ready to confess,' explained Regan in the clip, which was obtained by TMZ.
'I thought it was some kind of scam and I didn't believe him and I thought this guy's a lunatic, but I took his number and said I'd call him back. And the next day I called him back and he said he was willing to do it and the only condition that he had was he didn't want to call the book I Did It, he wanted to put an If in front of it so that he would have deniability with his children.'
She then added: 'He couldn't face his children and couldn't tell them that he had done it. That was the way it was portrayed to me.'
Simpson tells Regan in the special that he first saw Nicole when she was working at The Daisy, a popular Los Angeles club, and after failing to get her number during their first encounter went back a few days later.
Simpson confirms that he then began a relationship with Nicole, despite the fact that he was still with his first wife Marguerite, who had just given birth to their daughter Aaren at the time.
Nicole meanwhile had just graduated high school.
Simpson says he was in the process of separating from his wife, but they were slow to get a divorce because of the birth.
Simpson's love affair with Nicole, and how quickly the two became serious after meeting in 1977, was the focus of an entire episode of the Oscar and Emmy-winning documentary OJ: Made In America.
Simpson's friend Thomas McCollum III recalled his first trip to The Daisy with the football star, and the exact moment the then 30-year-old Simpson saw Nicole, who was still a teenager.
'He was married to Marguerite at that time, but as we're sitting there this gorgeous little surfer blonde is waiting tables at the lunch hour,' said McCollum.
'OJ goes, "Wow, who's that?" And Nicole came over and she said hello and she didn't walk ten feet away and he looks right at [owner of The Daisy] Jack Hanson and says: "I'm going to marry that girl."'
David LeBon was Nicole's roommate in Los Angeles at the time and said he was shocked at how quick it was happened, and the state his friend came home in after her first date with the former football star.
'She was 18-years-old. She had just graduated from high school. She was like my little sister,' said LeBon.
'She goes, "I met this man and his name is OJ Simpson."
'They went out and I waited up for them. She got home and it was like 2:00 in the morning and her jeans were ripped and I went "what happened?"
'And she goes, "well, he was a little forceful". And I go "Nicole, why would you let him on a first date be a little bit forceful?"'
He went on to say that Nicole told him that she really liked Simpson.
'That was the start of it,' said LeBon.
Two days later LeBon said that Nicole told him Simpson was buying her a car and getting her an apartment.
'I went, "Nicole, think about this." You know he's married and has children. And she goes, "but I think I really like this guy."
'It was that fast,' said LeBon. '18 years old. I mean, it was too young.'
The final person to speak during the first episode was Nicole's sister Tanya Brown, who spoke about just how in love her older sibling was with this man who was unknown to them despite his fame.
'We didn't know who he was. We're girls in the Brown house. We didn't grow up with football, we went to the beach,' said Tanya.
'We were like, "who are you?"'
She then added: 'They had a real love affair these two. When they were together it was just love.
'And that's what makes this thing so sad.'
