Kourtney Kardashian celebrated her Cosmopolitan cover with her sisters at the glossy’s 50th Birthday Celebration. She wore the family’s favorite brand in a $4,405 Balmain Black Pleated Stretch Jersey Jumpsuit:

Her black stretch jersey jumpsuit features a halter neckline, pleated detailing, open back, and wide-leg trousers.

Hot! Also loved her Kayu Arnette Clutch.

If you’re up for the splurge, get Kourtney’s jumpsuit here.

Thoughts?