The stars came out in force for Olivier Rousteing’s belated birthday bash in L.A.

Cara Delevingne, left, Omar Johnson and Kate Hudson were among those who made their way to a cabin overlooking the L.A. Basin to fete Olivier Rousteing.

Tyga gives a surprise musical performance at the Beats-hosted birthday bash for Balmain Creative Director Olivier Rousteing on Friday.

“Empire” star Jussie Smollett, left, poses with Balmain Creative Director Olivier Rousteing on Friday in Los Angeles.

Choreographer Casper Smart, left, singer Jennifer Lopez and Balmain Creative Director -- and birthday boy -- Olivier Rousteing pose for a shot on Friday.

From left, Jaime King, Kendall Jenner, Cara Delevingne, Kourtney Kardashian, Kim Kardashian West and Kylie Jenner attend a birthday party for Balmain Creative Director Olivier Rousteing on Friday at a private residence in Laurel Canyon.

Alessandra Ambrosio takes to the outdoor yard swing during the Beats-hosted bash for Balmain Creative Director Olivier Rousteing on Friday in Los Angeles.

Kourtney Kardashian, left, takes a selfie with Jaden Smith.

From left, Matthew Nozska, Olivier Rousteing, Jourdan Dunn and Abbey Lee Kershawn attend Rousteing’s birthday party in Los Angeles on Friday.

From left, Chanel Iman, Olivier Rousteing, Kim Kardashian West and Kourtney Kardashian pose on a paillette-covered couch high above Los Angeles on Friday at a belated birthday bash for Rousteing, Balmain’s creative director.