Kourtney Kardashian & Chrissy Teigen Party in Their PJs at Jessica Alba's Birthday Bash for Hubby Cash Warren

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Jessica Alba knows how to throw a pajama jam!

The actress’ A-list friends turned out in full force to celebrate her hubby’s birthday on Saturday night, donning onesies and playing beer pong to celebrate Cash Warren’s 38th.

“Love you babe!” Alba captioned a sweet Instagram pic of the couple in their comfy duds. “Last nights Pajama jammy jam was a blast! Love celebrating you with an epic pizza pajama game night! #happybirthdayCash.”

RELATED: Jessica Alba Throws Adorable Birthday Party for Watermelon-Loving Daughter Haven

Attendees at the laid back bash included Chrissy Teigen and John Legend, who donned a coordinating pair of KFC-inspired jammies for the night.

Kourtney Kardashian snapped a pic while snuggled up to the couple in her lacy, black evening wear.

PICS: Jessica Alba, Nicole Richie and More Attend Kate Hudson's A-List Halloween Party -- Including Her Ex Matt Bellamy!

Alba documented the entire evening on Snapchat, including the star-studded beer pong table, which saw a visit from designer and reality star Rachel Zoe. Other attendees included Pretty Little Liars star Shay Mitchell, Johnny Knoxville, and Nicole Richie with husband Joel Madden.

The Honest Company founder clearly loves going all in for birthday bashes. Check out how she and other A-list friends got their ‘50s on for Katy Perry’s sock hop-themed birthday bash last fall in the video below!

WATCH: Katy Perry Threw An Elaborate 'Grease'-Inspired Sock Hop For Her Birthday -- And It Was Amazing!