The 51-year-old star pulled fistfuls of hair over her face, gyrated on a sofa and sprawled next to singer Lenny Kravitz.
Wearing a tiny grey playsuit, black open-toe shoes and thick- rimmed geek chic glasses, Moore tugged at her outfit and danced about the club as guests looked on in confusion.
While the rest of the stars stayed seated and chatted among themselves, Charlie's Angels star Moore was determined to strut her stuff.
She jumped up to dance; thrusting her hips and clicking her fingers as she moved around the VIP area.
The atmosphere in the club looked extremely awkward, with fellow guests politely ignoring the star as she grinded next to them and/or slumped on top of them.
The Striptease star was attending Chanel's beachside barbecue event in Miami along with Kravitz and George Clooney's current squeeze Stacy Keibler. Earlier in the evening, Moore posted photos of herself with the Fly Away singer, but Lenny seemed to be cringing as Demi posed for cameras and spent most of the evening blanking the star.
This is the latest in a string of bizarre behaviour by Moore following the breakdown of her marriage to actor Ashton Kutcher.
The two parted last year after the Two And A Half Men star was caught partying with girls in a hot tub in a hotel room.
In January she was rushed to hospital following a binge on nitrous oxide and later entered rehab. Moore's weight plummeted after the break-up and she has been looking increasingly frail and anxious.