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"Did someone say Disco?" Khloé, 38, captioned an up-close, black-and-white shot among a carousel of images on Instagram. "Happy Birthday 👑🐝 🤍"
As for their chic looks for the party, Khloé brought the sparkle in a silver, sequined skirt and crop top while her 41-year-old big sister opted for a red and black tiger-striped jumpsuit.
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The morning after the celebration, Kim hilariously commented she was "still recovering lol."
The outing was one of Khloé's first since welcoming her second child, a son whose name has not been revealed. Khloé's child was fathered by ex-boyfriend Tristan Thompson, with whom she also shares 4-year-old daughter True Thompson. The couple confirmed their pregnancy via surrogate in July — shortly before welcoming their son.
Thompson, 31, was also seen in attendance at Beyoncé's disco birthday bash on Saturday. The event also offered Kim one of her first outings as a single woman after her split from Saturday Night Live alum Pete Davidson. PEOPLE confirmed the pair broke up in early August after nine months of dating. They were first linked shortly after Kim hosted SNL in October 2021.