Caitlyn Jenner's promise to Kris Jenner's ex Robert Kardashian on his deathbed

Caitlyn Jenner is shedding light into her relationship with the late Robert Kardashian Sr.

Jenner first came into the Kardashian world in 1990 when she met Kris and noticed that she was struggling with her divorce from Robert. Caitlyn took action to help mend the situation.

"[Kris] was having a rough time with Robert in the divorce when I came into the picture," Caitlyn revealed in the recently released "House of Kardashian" documentary.

"He was doing everything to kind of make her life miserable," she continued. "I saw what was going on from the outside and just said, 'This is ridiculous.' So, I called Robert up and said, 'Hey, let's go to dinner.'"

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"I basically said to him, 'Kris is moving on. Sorry, but she's moving on,'" she shared. "I said, 'I can take over from here. So, let's just make this final signing of the papers as simple as possible.' And he did."

The communication between Jenner and Kardashian didn't stop after the divorce was finalized. Caitlyn and Kris got married in 1991 and years later Caitlyn said she visited Robert on his deathbed and made a promise to him.

"He was really hurting," Jenner recalled in the documentary, adding, "and I said to him, 'Hey, remember if I was in your position, my only worry would be for my kids. That the kids are gonna get through this. I just want you to know that I will always be there for the kids.'"

Jenner continued, "And he says, 'Oh, you didn't have to say that. I knew you would.' And a week later he died."

Robert – who is the father of Kim, Kourtney, Khloe and Robert Kardashian – died in 2003 from esophageal cancer.

Before Kardashian passed away, Caitlyn and Kris welcomed their two daughters: Kendall and Kylie.

"House of Kardashian," the three-part docuseries, was released Oct. 8 on Sky Documentaries. The series was directed by Katie Hindley and produced by 72 Films.

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Caitlyn told Variety of her involvement in the docuseries: "I was happy to participate in the interview process to share my side, which points to the strength, influence and prowess my family has in captivating the world’s attention and keeping it over the years. I am incredibly proud of all my children and stepchildren."

Kris and Caitlyn announced their separation in 2013 after 22 years of marriage.