Happy Birthday, Scott Disick!

The reality TV star turned 33 on Thursday, and he celebrated one day later by partying at one of his favorite nightclubs, 1OAK inside The Mirage Hotel & Casino, in Las Vegas.

WATCH: Scott Disick Celebrates His 33rd Birthday With the Kardashians

Scott was joined by his ex-girlfriend, Kourtney Kardashian, her sister, Khloe Kardashian, and their close pal, Malika Haqq. The girls dressed to impress for the soiree, with Malika sporting an LBD that featured a plunging neckline and thigh-high slit, while Khloe impressively pulled off a skintight pink House of CB latex dress and Kourtney donned a bright green printed Versace dress.

The birthday boy kept it slightly more casual in distressed denim jeans, a basic black T-shirt and satin palm leaf bomber jacket.

The foursome kicked off their festivities with dinner and cocktails at STACK Restaurant and Bar before heading to the club around 1 a.m. Once they were inside the venue, they took a seat at a VIP table right behind DJ Shift and Kid Conrad's DJ booth.

PHOTOS: Khloe Kardashian Stuns in Skintight Latex Dress During Scott Disick's Vegas Birthday Party

They didn't forego desert at the soiree, as cocktail waitresses presented Scott with a black-and-white three-tiered Rolls-Royce themed cake that read "Happy Birthday Scott."

According to an eyewitness, Scott and Kourtney were whispering to each other inside their booth. Scott also exchanged a lot of laughs with Khloe, who was spotted snapping selfies with Malika and the DJs throughout the night.

Around 1:20 a.m., the DJs wished Scott a happy birthday and played 2 Chainz's "Birthday Song," which features lyrics like, "It's your birthday, it's your birthday" and "all I want for my birthday is a big booty hoe."

WATCH: Kris Jenner and Rob Kardashian Wish Scott Disick a Happy Birthday

In typical fashion, the girls took to Snapchat to share highlights from their fun night out, which included some screaming, lip-syncing and close-up shots of their clothes.

WATCH: Kourtney Kardashian Talks Hanging Out With Scott Disick 'as a Friend'

Prior to their arrival, Kourtney, Khloe and Scott documented their travel adventures as they made their way from Los Angeles to Vegas on a private jet.

WATCH: Kourtney Kardashian Wishes Scott Disick Happy Birthday With Throwback Pic

On Scott's actual birthday, the Kardashian-Jenner clan came together to help him celebrate in style, complete with cigars, a Japanese dinner and over-the-top ensembles.

To hear more on that celebration, watch the video below.