Scott Disick's pals are worried he is "out of control"

A source told E! News: "They fear he is out of control and has fallen off the wagon.

"He is partying hard and they are concerned."

Meanwhile, the 32-year-old television personality previously revealed he had "plans" to go back to rehab.

He shared: "The funny thing is, a lot of people were under the impression that I was going to this rehab facility in Costa Rica for a month, when the truth was, I was going for a week for one treatment that they have there. I'm not done. I plan to go back to this place.

"It's an amazing place. It's beautiful and I love it, but I wasn't able to spend three or four weeks there right now. I never planned on it, and everyone keeps telling me that I dropped out early."

Scott - who has five-year-old son Mason, two-year-old daughter Penelope and six-month-old son Reign with the 36-year-old beauty - also considered posting a photo of his plane ticket to prove he hadn't left the facility earlier than he was supposed to but eventually decided against it.

He added: "I wanted to actually Instagram or tweet a photo of my tickets that showed that I never intended to stay any longer than I stayed... I'm a work in progress and anything that I can do to better myself, I'm trying."