Watch Kourtney Kardashian Break Down and Call Sister Kim an 'Evil Human Being'

Kourtney Kardashian had some choice words for her sister Kim Kardashian West after the two had an intense argument. In a sneak peek clip of the upcoming Keeping Up With the Kardashians season 15 premiere, Kourtney calls Kim an "evil human being" when Kim attempts to apologize.

In the teaser, Kourtney breaks down in tears during a phone call with Khloe and their mom, Kris Jenner. "I'm not here to f—ing be mistreated by my f—ing b— family," Kourtney says before explaining that she's upset with Kim for calling her the "least exciting to look at" while the group was experiencing scheduling conflicts for their annual Christmas card photo shoot.

"You don't say things like that. You just just have really different values than me," Kourtney says. "I choose to be a mother to my three kids [Mason, 8, Penelope, 6, and Reign, 3]. I'm not here looking for another job. I already work enough, more than I would like to."

At that point, Kim walks in and hears the speakerphone conversation. "You don't do s—!" she yells at her older sister through the phone as Khloe runs outside in an attempt to make sure Kourtney doesn't hear Kim's remarks. Jenner warns her daughter, "Don't be mean, Kim!"

Kim, head of KKW Beauty, tells Kourtney that she and Khloe "have more jobs" so Kourtney should "work around" their schedules for the photo shoot. "You don't do s—. Be accommodating to the people that actually do s—," she adds.

"You're a very distraught, evil human being," Kourtney responds. "I don't wanna see you, OK? I don't agree with who you are as a human being."

After a half-hearted apology interspersed with giggles, Kim says Kourtney is "clearly going through something else" because she's "acting like a f—ing lunatic."

Jenner and Khloe look shocked at Kim's statement, with Jenner intervening, "That's not OK to say," but Kim continues: "You're the most f—ing entitled person on the planet when you work the least."

Previously, Kourtney had stormed out of a meeting with Kim, Khloe and Jenner after Kim asked Kourtney to reschedule her day so they could get the photo shoot done. When Kourtney refused, Kim called her the "least interesting to look at" out of all members of the family.

While things seem dire between the sisters in the clip, fans of the show know that they eventually worked out their issues, as Kourtney appeared in the Christmas card and even shared the photos via her social media channels.

To see how the fight resolves itself, tune into the Keeping Up With the Kardashians season 15 premiere on E! Sunday, Aug. 5 at 9 p.m. ET.