The long-running reality TV series documenting the highs and lows of America’s thirstiest family reached a new low on Thursday night when sisters Kim Kardashian and Kourtney Kardashian got into a physical altercation during Season 18’s premiere episode.

During a virtual interview with Jimmy Fallon on Monday’s Tonight Show: At Home Edition, he asked Kim about what led up to the brawl between her and her sister Kourtney.

“I feel like it’s been a lot of built-up resentment from Kourtney, or just feeling like she doesn’t really wanna film anymore,” Kim said during the interview. “And she’s not the type of person to make a decision and say, ‘Ok guys, I’m not gonna film.’ But she would come to work every day with an attitude and kind of take it out on everyone from the crew to us and wouldn’t really make that decision. We would keep on pushing her to find out why she was so unhappy. I don’t really ever resort to violence like that but she scratched me so hard, which you guys didn’t see… I was bleeding. You didn’t really get to see that detail, but when I looked down at my arm and saw she had really scratched me and felt it all in my back, I just, you know, went over and slapped her back. So it’s not, like, my proudest moment, but we were going through it and she’s made the decision to take time off now and I think she really needs it. And I think that will be so much better for her.”

100 CELEBRITIES WHO DIED IN 2019 – TRIBUTE SLIDESHOW

Kim says production on Season 18 of Keeping Up With The Kardashians shut down for a week after the sisters’ fight and the siblings are “obviously fine now,” but when their mother, Kris Jenner, saw a clip of their behavior “she cried.”

The Kardashians’ reality series was one of the many, many shows that had to prematurely halt filming due to concerns over the coronavirus pandemic, including late-night series.