Ch-ch-changes! Something’s different about Khloé Kardashian’s face — and Kim and Kourtney want an explanation. In a preview for the season 11 finale of Keeping Up With the Kardashians, the reality star’s big sisters question her about (and even laugh at!) her new frozen-faced look.

"Khloé, I was gonna call you and talk to you last night about this,” Kim, 35, tells the Strong Looks Better Naked author over the phone. "Your whole face has changed. Did you do any filler?"

“No, I haven’t!” Khloé promises.

“[She has] the craziest laugh,” Kourtney chimes in, unable to stop her own guffaws.

“You haven’t done any Botox?” Kim presses further. “Khloé, your whole face changes when you laugh. It's like, I stare at you.”

“No way, you guys!” Khloé insists. “I think it’s because I’m forcing a fake laugh.”

“No, you’re really laughing,” Kim says, before double-checking with Kourt: “You noticed it?”

“Yes!” Kourtney nods. Kim then offers up an alternative theory for Khloé’s unfamiliar mug.

"I thought she was on drugs," the mom of North, 2, and Saint, 2 months, admits. Echoes Kardashian BFF Jonathan Cheban: “I did too!”

To see how Khloé responds, watch the hilarious teaser above.

The season 11 finale of Keeping Up With the Kardashians airs Sunday at 9 p.m. on E!

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