“Keeping Up With the Kardashians” star Khloé Kardashian often shares her love for her brother, Rob Kardashian, but she was noticeably absent at his 29th birthday celebration Saturday. She was the only member of the family who did not attend the bash.

Her mother, Kris Jenner, explained her daughter’s health and frantic career is what kept her away from the party. “She was working and then she was sick and just had a crazy ... yeah,” Jenner told Entertainment Tonight Online at the Daily Front Row’s Fashion Los Angeles Awards Sunday night. “I’m not even sure if she was working in or out of town. It’s just so crazy.”

But the E network’s reality-television family made the most of Rob’s party. “We had a good time, and we picked a night that most all of us could be in one place at the same time,” Jenner said.

Both Kourtney Kardashian and Kim Kardashian West posted photographs of the event on social media. While Kourtney simply captioned hers, “Fam,” Kim wrote, “Familia.”

Khloé, 31, confirmed she was sick over the weekend in a social media post. “The kiddies got me sick,” she wrote Saturday, referring to her nieces and nephews. “Feeling like s--- today. Take your vitamins world.”

After missing Rob’s birthday celebration, the “Strong Looks Better Naked” author opened up about staying in contact with her exes. “Just because you break up with someone doesn’t mean you lose that connection,” the New York Daily News quoted her as writing on her website Monday. “I always want to feel like I can say hi to anyone I’ve had a relationship with if I saw them in public. I never want to go anywhere and be nervous because so-and-so is there.”

Khloé also feels that way about Scott Disick, who is Kourtney’s on-again, off-again boyfriend of nearly a decade. “He was a huge part of our family and always will be,” she said.

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