Nicole Simpson Brown continues to haunt the thoughts of her friend Kris Jenner more than 20 years after her brutal murder.

In an interview with Ellen DeGeneres on Monday, Kris Jenner said she’ll “always feel horrible that I didn’t pay enough attention” before Nicole met her untimely death.

Jenner, who was close friends with both Nicole and O.J. Simpson, revealed new details about what happened in her world after Brown’s death.

Kris Jenner remembers her last moments with Nicole Simpson Brown – https://t.co/0X7qZBFvkX pic.twitter.com/gTAOCXpebu

— Yahoods! (@YaHoodstweet) February 15, 2016

Jenner was famously married to Robert Kardashian Sr. who was one of O.J.’s closest friends and became one of the accused killer’s legal dream team.

The relationship between the four friends is chronicled in the FX miniseries American Crime Story: The People v. O.J. Simpson, which tells the story surrounding the “trial of the century” from the lawyers point of view.

Jenner, 60, told DeGeneres that the portrayal of tension between Kris and Robert over his commitment to defend O.J. on the series is accurate.

“It was very difficult because my ex-husband was on one side and I was kind of on the other, and the kids were in the middle,” said Jenner.

Kris said she’d actually made plans with Brown to go on a lunch date the day after her death and believes that Nicole Brown had plans to reveal to her that Simpson was abusing her.

.@KrisJenner still haunted by Nicole Simpson Brown's murder: https://t.co/UMU1bWUiQ6

(Via @HuffingtonPost) pic.twitter.com/GDKYBE27vl

— CELEBUZZ (@CELEBUZZ) January 28, 2016

“I didn’t know that there was abuse until we heard and saw the whole thing unfold like everyone else, and then heard the 911 tapes…which were going to be used as evidence during the trial,” Jenner said. “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.

“She and I were supposed to have lunch the next day-the day after she was murdered-and she said she wanted to show me some things and talk about what was in her safe,” Jenner continued.

“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’ll always feel horrible that I didn’t pay enough attention.”

Kris Jenner says O.J. Simpson called her right after Nicole Brown Simpson's murder https://t.co/8xKJtrvW9L pic.twitter.com/pHpBHvWwLG

— People Magazine (@people) March 1, 2016

Kris Jenner, 60, said she had known Simpson since she was 17 and considered him to be “like a big brother” to her.

According to Kris, Simpson attempted to contact her after Brown’s death but the reality star did not give specifics on any conversation they may have had.

“[He called me] right after, yeah,” Jenner said. “He called me a few times, and you know, wanted to talk and explain how he felt.”

American Crime Story: The People v. O.J. Simpson airs 10 p.m. EST Tuesdays on FX.