Celine Dion 'praying for a miracle' amid battle with stiff person syndrome

Celine Dion's sister says she is "praying for a miracle" after the legendary singer revealed her battle with stiff person syndrome late last year.

"She's doing everything to recover," Claudette Dion, 74, told Hello!

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Claudette says family find it hard to help Celine, 55, as "little" is known about the illness that causes spasms in the body "impossible to control".

Celine previously was forced to postpone some tour dates due to her battle with the condition, which she said was affecting her voice.

It doesn't let her "sing the way I'm used to," she previously said.

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Stiff-person syndrome is a very rare neurological disorder that affects the nervous system, and specifically the brain and spinal chord.

According to the National Institute of Neurological Disorders and Stroke, symptoms of the disorder can include "extreme muscle stiffness, rigidity and painful spasms in the trunk and limbs, severely impairing mobility.

Celine made the announcement in a video clip shared to social media, assuring fans she is doing everything she can to keep her symptoms at bay.

"I'm working hard with my sports medicine therapist every day to build back my strength and my ability to perform again," she said. "But I have to admit it's been a struggle."

Celine's late husband, Canadian talent manager and music producer René Angélil sadly passed away in 2016 from throat cancer. He was 73.