The Kardashians are no strangers to throwing fabulous, over-the-top fêtes — so when Kourtney Kardashian announced her fashion collaboration with U.K. retailer PrettyLittleThing, we knew the launch party was going to be just as amazing as the collection.

So what actually happened when the stars showed up to celebrate the mother of three’s clothing and shoe line last night at L.A.’s Poppy Nightclub? For one thing, “P. Diddy stole the show,” reports an eyewitness. The rapper took the stage just before midnight to sing a medley of his hits (and praise Kardashian’s line, of course) and the “crowd went crazy.” Other  partygoers included Lori Loughlin, Teyana Taylor, Kar-Jenner BFF Malika Haqq — and Vanderpump Rules‘ Tom Sandoval!

Though no other members of the Kar-Jenner clan seemed to be available to celebrate, the reality star did get support from her boyfriend, model Younes Bendjima. “Younes was by Kourtney’s side the whole night,” shares an onlooker. “They were laughing and talking.”

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