The Kar-Jenners are up to their old tricks again!
In this clip from Sunday's all-new Keeping Up With the Kardashians, Kim Kardashian and Kylie Jenner reveal who's been poisoning their mom Kris Jenner, but they're not doing it because they're concerned for her health.
"Oh my God, we have to f--k with mom," Kim tells Kylie. So, the sneaky sisters call their mom to break the big news.
"Hi mom," Kim says. "It's me and Kylie. We figured the whole thing out." "What'd you figure out?" a curious Kris asks.
"That Kourtney has been poisoning you this whole time," Kim reveals.
The revelation comes as a bombshell for the momager who had just tested her drinking water for poison with daughter Kourtney Kardashian.
"Stop. No way! I just was with her. Why would she do that?" Kris wonders.
"Just because she's, you know, has been trying these new all gluten-free organic drops and we think that she's been adding these things to our food," Kim says, trying to hold back her laughter.
Despite Kim's chuckles, Kris seems to believes her daughter's crazy confession.
"Stop. She's insane," Kris responds. "Well, you know she made me throw away all of my Tupperware. She must be doing the drops to reverse the process."
The conversation turns out to be too much for Kim and Kylie who are laughing so hard, they end up hanging up on their mom.
See the hilarious prank in the clip above!