Scott Disick faced the wrath of his ex Kourtney Kardashian's sisters and mother when he joined them at dinner while on vacation in Costa Rica.

In a preview clip for Sunday's Keeping Up With the Kardashians, the father of three joins Kourtney, Kim, Khloe, Kris Jenner and Cory Gamble at the dining table, unaware that they know of the woman, Chelsea, that he's brought on the family getaway.

Watch: Scott Disick Admits Kourtney Kardashian Still Turns Him On, Says He'll 'Never Be Over Her'

Tensions rise as the ladies refuse to tell Scott right out about what they know, but he soon catches on when Kim asks, "Did you guys hear what Chelsea said?"

"Oh, yeah," Khloe responds. "She's such a b**ch."

The sisters pretend to be talking about Chelsea Handler and Chelsea Clinton, but Scott is onto them. "Let's cut the bulls**t," Kim finally says.

Watch: Kourtney Kardashian and Scott Disick Are 'Back...