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Katfight! Kim Kardashian and sister Khloe Kardashian always have each other's backs -- except when they're at each other's throats. As seen in this preview of the July 27 episode of "Keeping Up With the Kardashians," things get tense between the siblings on the family's vacation to Thailand, when Khloe decides to "get the freak out of [there]" early.

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Kim, 33, doesn't understand why her younger sister, 30, is so eager to leave and travel alone, and she has no problem saying so. Her disapproval doesn't sit well with Khloe, who responds by mocking Kim's rather obsessive habit of taking pictures of herself.

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"Why don't you go take some more selfies?" she quips.

"I'm doing it for Kanye, someone that I love," Kim replies, to which Khloe sarcastically retorts: "One day I'll be so lucky."

Clearly annoyed, Kim fires back with a diss about Khloe's post-split relationship with French Montana. "You want to get home to the 50 rappers you're dating," she says. "You're, like, a miserable person."

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Keeping Up With the Kardashians airs Sundays at 9 p.m. ET/PT on E!