The latest episode of Kourtney and Kim Take Miami revealed a shocking threat Rob Kardashian made to his older sister Kim Kardashian.

Kim revealed in Sunday's episode during a phone call to her mother, Kris Jenner, that when Rob asked her to ask her boyfriend, Kanye West, if the rapper will collaborate on a song with Rob's friend, she declined. Kim then told their mother that Rob replied via text message: "He said: "I hope your sex tape haunts you for the rest of your life and I'm going to publicly bash you and Kanye."' 

Kim shared Rob's threat after she and Kourtney were helping Rob deal with his breakup with British singer Rita Ora. They had just advised Rob to cease talking to Ora.

"She's the one that's in the wrong but she'll probably try to make it like you're in the wrong," Kourtney told Rob.

Kourtney was referring to Rob's infamous Twitter rant in November when he tweeted (then deleted) that "she" (possibly referring to Ora), "cheated on me with nearly 20 dudes while we were together."

Kim weighed in her opinion on how Rob should handle his breakup. "Don't post anything else. Everyone has problems," she told him.

"I don't want people to think I'm being a bitch," Rob replied.

Kim then said ever since Rob broke up with Ora he has been "dating all these girls that I don't think are his type."

Kim then called their mother and revealed Rob's shocking threat and reference to her infamous sex tape.

Later, Rob called Kim to apologize for his comments while she is having dinner with West, Kourtney and her son Mason.

"I wanted to apologize," Rob told Kim over the phone. "Obviously the things I said to you in the text message, I was just being mean."

"I appreciate you being mature and calling me instead of dragging this fight out," Kim replied to him.

Rob had tweeted then deleted a series of explosive tweets that alleged that Ora cheated on him during their relationship last year. 

"She cheated on me with nearly 20 dudes while we were together, I wonder how many she will sleep with now that we apart? But I mean 20?!!!," Kardashian tweeted on Nov. 29. "How can a woman who is so busy trying to start her own career have time to be with so many dudes all while in a relationship?!"

The following week, Ora cited the long distance between them as the reason for their breakup in the January 2012 issue of Glamour U.K.

"I'm not going out with Rob. We were close for a while, but it didn't work because I was never there," Ora told Glamour UK magazine, according to Daily Mail.