Inside Kourtney Kardashian's 40th birthday party

Another Kardashian party down in the books!

Kim, Khloe, Kendall and Kylie all stepped out on Thursday night to attend their oldest sister, Kourtney Kardashian's, 40th birthday party.

The mom-of-three wore a vintage Versace gunmetal metallic sheer dress and made a sweet entrance holding her daughter Penelope's hand, while a saxophone player played Stevie Wonder’s “Isn’t She Lovely.”

Inside the intimate party, Robin Thicke and an unmasked Sia performed, while guest lined up to the Don Julio custom bottle engraving station underneath a ceiling of sparkling lights.

Her cake? A sculpture of one of Kourtney's most famous photos sitting nude on the edge of her bathtub. The party decor also poked fun at the birthday girl, with napkins and liquor bottles reading 'most Interesting to look at’ - a reference only Kardashian fans would understand.

The guests list included Paris Hilton, Kanye West, Quavo, Travis Scott, Luka Sabat, Johnathan Cheban, French Montana, Charlotte Lawrence and Domenico Dolce of Dolce and Gabbana. Kourt's ex-boyfriend Younes Bendjima also attended as did Scott Disick, the father to her three children. Disick brought his longtime girlfriend, Sofia Richie, to the party as well.

Mom Kris and grandma MJ were also at the party, however step-dad Caitlyn Jenner was missing in action. Earlier in the evening Caitlyn took to Instagram to share a sweet post for Kourtney.

"It has been one of the greatest joys in my life to watch you grow in so many ways. You are an amazing mom to your kids. You are an amazing business woman. And above all else a kind soul. Happy birthday @kourtneykardash PS you’re catching up to me," the caption read.