Los Angeles, California - Khloé Kardashian has opened up about the medical emergency that led her and her little ones to miss the famous family's annual Christmas Eve bash.

The 40-year-old reality star was MIA from the holiday party on Tuesday, and two days later, she took to social media to reveal what happened.

In a video shared to her Instagram story, Khloé explained that her two-year-old son, Tatum, had been "super sick" the weekend before the holidays but had recovered by the time Christmas Eve rolled around.

His older sister, six-year-old True, wasn't so lucky.

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"True had a 105 fever," Khloé said. "It was really scary. It was horrible. Now she’s just starting to feel better."

The illness meant that the Revenge Body star skipped out on the annual Kardashian-Jenner party – though the affair was a more low-key event due to construction at matriarch Kris Jenner's home.

Khloé added that True still wasn't feeling her best on Christmas Day, so they opened the gifts from Santa the following day instead.

"Poor thing, that's when you know your kid is sick, when Santa toys don't even excite them," she said. "I'm so happy she's feeling better."

Khloé shares both True and Tatum with her ex, NBA star Tristan Thompson.