Obviously his presence was well-documented by onlookers on social media. Here he is walking the red carpet:
A couple lucky fans got to rub elbows with him in the VIP area.
"VIP treatment plus a meet and greet with The Lord himself!" wrote one admirer, referring to Disick's preferred nickname for himself (his Instagram handle is @letthelordbewithyou).
Another caught a blurry shot of him playing poker at the Mirage before the party.
People Magazine caught up with Disick to talk about his stint in rehab. He told them he had only planned to stay at the Rythmia Life Advancement Center for one week in mid-March.
The facility specializes in a treatment using an African root called Ibogaine, which has some hallucinogenic properties. Ibogaine is used to treat addiction and chronic pain issues. Disick said it has helped him dramatically, and that he plans to undergo the treatment again.
"I'm not done. I plan to go back to this place," he told People. "I'll go back when I want to and get some more treatments. And, listen, I really love it and I think it helped me. Obviously I'm not a perfect human being yet, but maybe down the road I'll be pretty close to it."
ET sat down with the founder of Rythmia Life Advancement Center to discuss how they use hallucinogenic drugs to treat addiction.