The 24-year-old said she was “feeling herself” when she posted the impressive ab snap.
“I rarely post pics with my belly button showing because I'm normally insecure about showing my full stomach but I've been working really hard and thanks to @d.leith and his yummy food with @lockhartandleith I've been seeing progress.”
She also thanked her trainers, Jason Borba and Kim Glass, as well as her gym, Unbreakable Performance.
Demi credits exercise as a huge part of her healing process after battling bulimia and bipolar disorder.
“Exercising has been so important for my recovery, both physically and mentally," she told Fitness Magazine. “On show days I count my concert as a workout, but on my off days I try to work out once in the morning and again at night. It can be a lot between performing and traveling, so I'm careful not to push myself too hard.”