Céline Dion is revealing more details about her health journey.

The "My Heart Will Go On" singer reflected on the remedies she tried amid her battle with stiff-person syndrome, including up to 90 milligrams of prescription medications like Valium—which can treat muscle spasms—to get her through performances.

"Ninety milligrams of Valium can kill you," Céline told Hoda Kotb during NBC News' hourlong special Celine's Story. "You can stop breathing. And at one point, the thing is that my body got used to it at 20 and 30 and 40 [milligrams] until it went up."

"And I needed that," she continued. "It was relaxing my whole body, but for what? For two weeks, for a month—'OK, the show must go on. Here we go, I'm fine'. But you get used to it, it doesn't work anymore. More, more, more."

The Grammy winner recalled taking 20 milligrams of the medication and by the time she walked from her dressing room to backstage, the relief had worn off. But singing was her passion. So, when the Covid pandemic shuttered live performances, it allowed her to focus on her health without canceling shows.

But the 56-year-old also added, "I stopped everything because it stopped working so I got worse."

After over 20 years of muscle spasms and extreme pain that resulted in painful performances and canceling tour dates, she was diagnosed with stiff-person syndrome in 2022. 

And one of the hardest battles for Céline—who shares sons René-Charles, 23, and twins Nelson and Eddy, 13, with her late husband René Angélil—was struggling to perform. "I wanted to be brave," she admitted. "I didn't want to let anyone down."

But since her diagnosis, she's continued to remain positive amid her harrowing battle and is grateful for the support from her friends, family, fans and team.

"Life doesn't give you any answers," she told Vogue France in April. "You just have to live it! I have this illness for some unknown reason."

"People who suffer from SPS may not be lucky enough or have the means to have good doctors and good treatments," she shared. "I have those means, and this is a gift. What's more, I have this strength within me. I know that nothing is going to stop me."

Keep reading to learn more about Céline's battle with stiff-person syndrome.

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The COVID-19 pandemic had forced Céline Dion to press pause on her Courage World Tour in 2020 and she was looking forward to getting back on the road in 2022. But that spring the singer said she'd be postponing her return until February 2023 while she continued to deal with a lingering health issue.

A note on her website further explained that she'd been treated for "severe and persistent muscle spasms which are preventing her from performing, and her recovery is taking longer than she hoped."

Dion said in a statement, "I need to be in top shape when I'm on stage. I honestly can't wait, but I'm just not there yet… I'm doing my very best to get back to the level that I need to be so that I can give 100 percent at my shows because that's what you deserve."

Dion shared that she had been diagnosed with a "very rare" progressive neurological disorder called stiff-person syndrome, surely the first time that most people had ever heard of it.

"As you know, I've always been an open book," she said in an Instagram video. "I wasn't ready to say anything before, but I'm ready now. I've been dealing with problems with my health for a long time, and it's been really difficult for me to face these challenges and to talk about everything that I've been going through."

She suffered muscle spasms that affected "every aspect" of her daily life, Dion explained, making it difficult to walk sometimes and, saddest of all, it was going to be impossible for her to go back on tour as she'd been planning.

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

According to the National Institutes of Health, symptoms include stiff muscles in the torso, arms, and legs, and greater sensitivity to noise, touch, and emotional distress, all of which can trigger muscle spasms.

Who says you can't have some new Céline Dion music when you least expect it? 

She had previously recorded five songs for the rom-com Love Again, and the title track dropped ahead of the film's May 5 release. "I think it's a wonderful feel-good story, and I hope that people will like it, and like the new songs too," stated Dion, who also appeared as herself in the movie starring Priyanka Chopra Jonas and Sam Heughan.

Dion already had several signature movie tracks to her name—"Beauty and the Beast," "Because You Loved Me" and the Oscar-winning Titanic anthem "My Heart Will Go On"—but somehow she had never been in a movie before. (You can check out her debut in this one on Netflix.)

After a three-month delay, Dion canceled her Courage World Tour entirely through April 2024.

"I'm so sorry to disappoint all of you once again," she wrote on Instagram. "I'm working really hard to build back my strength, but touring can be very difficult even when you're 100 percent. It's not fair to you to keep postponing the shows, and even though it breaks my heart, it's best that we cancel everything now until I'm really ready to be back on stage again."

Dion was seen out in a very public place for the first time since she shared her diagnosis when she caught a Las Vegas Knights hockey game at T-Mobile Arena with her and late husband René Angélil's three sons, René-Charles, 23, and twins Eddy and Nelson, 13.

The Montreal Canadiens shared footage of the family's meet-and-greet in the visiting team's locker room, Dion telling coach Martin St. Louis (per an English translation) that it had been "an incredible night." She even gave the players a pep talk, advising, "Just stay healthy, strong...do what you do best."

But better yet, according to Canadiens executive Chantal Machabée, their VIP guest sang "a few notes" for them and it was "an incredible moment."

"She's been through a lot, and to see her like this and smiling and being so happy...it's amazing," the team's VP of hockey communications told People. "I know she has good days and not so good days, but this was a very good day, and it was reassuring."

Claudette Dion gave a rather dire-sounding update on her sister's health battle, telling 7 Jours (translated from the original French) that the singer—who's the youngest of 14 siblings—didn't have control over her muscles.

"What breaks my heart is that she's always been disciplined," Dion's big sister said. "She's always worked hard. Our mother always told her, 'You're going to do it well, you're going to do it properly.'"

The former judge on Quebec's L'Étoile des aînés (a competition for singers 65 and older) said it was her and Dion's dream that the singer would be able to return to the stage. "In what capacity?" she added. "I don't know."

The most promising sign yet that a new day had begun: Dion, who had understandably chosen to take a step back from public life while she battled her condition, was getting ready to give a raw look at what she was going through. 

Amazon announced the upcoming documentary I Am: Céline Dion, directed by Irene Taylor, would reveal the lengths Dion had been going to in hopes she could go back to doing what she loved.

"As the road to resuming my performing career continues, I have realized how much I have missed it, of being able to see my fans," Dion said in a statement, explaining why once more she was opening the door. "During this absence, I decided I wanted to document this part of my life, to try to raise awareness of this little-known condition, to help others who share this diagnosis."

The 2024 Grammys may have ended with a few more people believing in the power of love.

As soon as Dion was announced as the night's final presenter (after social media got wind of her presence elsewhere in the building, but still), the audience was on its feet.

The five-time Grammy winner may not have been ready for a spotlight performance on music's biggest night just yet, but she did sing a few bars with Sonyaé Elise backstage, the "Collide" artist sharing the moment on Instagram afterward amid other highlights from her "ICONIC night."

Dion and Taylor Swift also shared an off-stage hug, silencing the immediate uproar over Swift seemingly not paying proper homage to the elder legend onstage when Dion presented her with Album of the Year for Midnights. Not wanting to be an anti-hero on her history-making night, Swift posed for pics with Dion and René-Charles, who had sweetly escorted his mom to the microphone.

Dion also shared some highlights from the icons-only portion of the evening, including photos with Stevie Wonder and Oprah Winfrey.

Celebrating the momentous night with Dion was her longtime stylist Law Roach, who dressed the star in a flowy Valentino dress and striking overcoat, with Tiffany & Co. diamonds upping the sparkle factor.

"This makes me so much Joy!" he captioned a next-day Instagram snap with Dion. "Not just to dress my Queen again but the fact that she's HEALTHY AND HAPPY! The UNIVERSE always PROTECTS and PROVIDES."

After a March trip to Boston, where she watched the Bruins take on the New York Rangers at TD Garden, Dion gave an update on her health to Vogue France.

She was still learning to live with stiff-person syndrom, she shared in the article published April 22, but was working her butt off with athletic, physical and vocal therapy five days a week to not let it defeat her.

"The way I see it, I have two choices," Dion said. "Either I train like an athlete and work super hard, or I switch off and it's over, I stay at home, listen to my songs, stand in front of my mirror and sing to myself."