Celine Dion revealed she had a rare illness that limited her ability to sing, which surprised everyone, including her own sister.

According to Hello, Dion’s sister, Claudette, opened up about the singer’s stiff-person syndrome diagnosis, which she initially mistook for another condition.

She said:

“Firstly, I always say that if Celine wasn’t well, we would know about it. It would be impossible for her not to tell us.”

She continued:

“Secondly, she wouldn’t have postponed her shows, she would have canceled them. These have just been postponed.”

She eventually admitted that she believed Dion was simply going through menopause.

“I’ve told her – you’re just being menopausal, calm down.”

According to the National Institute on Aging, menopause occurs when a woman has not menstruated for 12 months.

According to the Mayo Clinic, signs of menopausal transition include hot flashes, decreased energy, disturbed sleep, and other symptoms.

This transition period begins at different ages for different women, but the range is between 45 and 55, and the “The Power of Love” singer is currently 54 years old, according to reports.

Dion may have shared some of her stiffness with her sister, and Claudette assumed it was just menopause.

Claudette added:

“It’s true that she does have muscle spasms; I’ve seen her myself with her little leg all twisted.

Several people who know Celine well after working with her often ask me whether the iconic Caesars Palace stage slope might have damaged her nerves or the muscles in her pelvis.”

Despite the rare disorder, Dion’s sister assured fans that the singer is being cared for and will be able to perform again soon.

“She is being looked after, she’s getting plenty of massages, she’s making the most of it and being pampered. She’s going to return to the stage, I’ve heard that rehearsals are finished and it’s going to be crazy.”

According to reports, stiff-person syndrome, also known as Moersch-Woltman syndrome, is a “rare neurological disorder with autoimmune disease features.”

Furthermore, because the disorder is so uncommon, it is frequently misdiagnosed as other autoimmune disorders.

Or, for someone without a medical background, like Claudette, it could be misdiagnosed as another illness or condition entirely.

The “My Heart Will Go On” singer has canceled and rescheduled several shows as of this writing. According to recent reports, the singer lamented her disorder, saying, “Unfortunately, the spasms affect every aspect of my daily life,” making performing difficult.