In a new sneak peek clip for Sunday's episode of Keeping Up With the Kardashians, the two eldest siblings of the Kardashian clan get into a heated discussion about their daughters, North West and Penelope Disick's, joint birthday party.
The two cuties had decided on a Candyland-themed bash over the summer, but Kourtney was seemingly having second thoughts about how unhealthy the party would be.
"It's a completely sugar-free, gluten free, party-free, fun-free zone because Kourtney has decided that," Kim says in an aside interview. "It just doesn't make sense, and it really wasn't the theme of what North and Penelope wanted for their birthday."
But Kourtney is adamant, saying, "There's just better solutions to things instead of your dated candy that's literally food coloring that gives people diseases."
When Kim points out that Kourtney's views go directly against the Candyland theme, she fires back, "So switch the theme. My brand is not unhealthy."
This comment prompts Kim to scoff, saying, "Your brand? This is about a kid's party. This is not about your brand."
"Yeah, but I'm saying what I stand for. Not even a kid's party," Kourtney replies.
"Then why does your car have leather seats? Why are you wearing plastic glasses?" Kim claps back, calling out Kourtney on her double standards.
In an aside interview, Kourtney tells viewers, "I can't believe that Kim is not willing to compromise at all and that she doesn't feel guilty about giving not only her kids and my kids but all these kids that are coming to our party so much junk and candy. It's such a dated vibe to be like that."
The spat ends with Kim saying, "I want a fun kids party with real candy," and Kourtney answering, "Well, that's your problem."
We know that the theme ended up staying Candyland, but it's unclear whether Kim got to keep her birthday treats or if Kourtney's healthier options won out.
This isn't the first time the sisters have gotten into it this season. The pair got into a shouting match over Kim's humanitarian efforts. Kourtney recently opened up to ET about the possibility of stepping back from the family's reality series.
"I just decided to spend more time as a mom and put more of my energy there," the mother of three said at the time. "But I'm not saying goodbye."
For more from the exclusive interview, watch the clip below: