AceShowbiz - The Kardashian sisters are truly prank sisters. Kourtney Kardashian has a sweet revenge for Kim Kardashian that successfully embarasses the latter. In a new clip for a new episode of "Keeping Up with the Kardashians" season 15, the eldest Kardashian sister pulled a prank on the KKW Beauty founder by performing a flash mob dance at a local mall.

Alongside Khloe Kardashian, Kim was out for a quick ice-cream errand when people suddenly started dancing to The Pussycat Dolls' "Buttons". The mother of three was visibly confused, asking Khloe, "What the f**k is going on?"

Kourtney and their friend Malika Haqq could be seen dancing in the crowd, making Kim stunned and a bit nervous. At one point, Khloe joined the two briefly, and that made Kim realize that Khloe was part of the prank. "Don't tell me you know it too," Kim told Khloe in disbelief.

It turned out that the prank was a sweet payback after Kim sabotaged a dance class they took together. "After you ruined our dance class with your critiques, I thought it would be funny to embarrass you. Did I succeed?" Kourtney said in the clip. "You did," Kim replied.

"I'm literally dying inside over this flash mob," Kim admitted in her confessional. "I just can't even believe you guys. I'm gonna have to run if they try to pull me into this."

The famous sisters are set to show more of their prankster side on an upcoming show "You Kiddin' Me?" on Facebook Watch. Meanwhile, season 15 of "Keeping Up with the Kardashians" airs on Sundays at 9 P.M. on E!.