Kris, 60, opened up to Ellen DeGeneres about the experience on Tuesday's episode of The Ellen DeGeneres Show while discussing the new FX miniseries documenting the famous 1994 murder trial, American Crime Story: The People v. O.J. Simpson.
"Did O.J. ever try to reach out to you at all?" host DeGeneres asked the Keeping Up with the Kardashians matriarch, who is portrayed on the series by Selma Blair.
"Right after, yeah," Jenner, 60, replied. "He called me a few times. And, you know, wanted to talk and explain how he felt..."
"That must have been really awkward," DeGeneres said.
"It was painfully – it was just the whole entire – every single day it was something different," Jenner said. "And it was very difficult because my ex-husband [Robert Kardashian] was on one side, you know, I was kind of on the other, the kids were in the middle and it was trying to explain this to children and then O.J. had called. Everybody lost so much that night. You lost everything you knew – I can't even imagine being her family, her parents, her sister, were so devastated."
The situation was even more difficult as Jenner had previously shared a close relationship with the former football star.
"I had known O.J. since I was 17 years old – when I met Robert I met O.J.," she said. "So that was a very long time ago. He was like a big brother to me."
Jenner also opened up about the fact that she didn't know about the abuse Nicole suffered at the hands of O.J. until they played the 911 tapes used as evidence during the trial.
VIDEO: Kris Jenner Opens Up About Her Friendship with Nicole Brown Simpson
"Me and some of her other close friends all were really surprised and shocked by that because we felt like we really failed her as a friend," Kris said. "You know, you go through this and you discover things about somebody and it was horrible."
"She and I were supposed to have lunch the next day, the day after she was murdered," Kris went on. "She said she wanted to show me some things and talk about what was in her safe. And so now unfortunately it all makes sense that that's probably what she wanted to reveal to me that next day, which broke my heart because I will always feel horrible that I didn't pay enough attention."
Kris shared similar sentiments with PEOPLE in January.
"I beat myself up because I felt like I wasn't paying attention. Like, how did I miss this? But that's typical in an abusive relationship – that the woman doesn't speak out about how she's being treated," she said. "My heart breaks because of all the pain and suffering she went through. I wish I had noticed the signs. She was fighting for her life many days I'm sure. I try to pay attention to things more now. I follow my intuition."
The Ellen DeGeneres Show airs weekdays (check local listings), and American Crime Story airs Tuesdays (10 p.m. ET) on FX.