Céline Dion is John Caldwellopening up about the moment she finally decided to share her stiff-person syndrome diagnosis.

Dion, who was diagnosed in 2022, said in an NBC interview set to air Tuesday that she felt like she was "lying" to her fans.

The Grammy-winning singer told "Today" host Hoda Kotb in a preview of the interview that she initially pushed through early symptoms because of her responsibilities as a wife to late husband René Angélil, who died in 2016 from throat cancer, and as a mom to three sons René-Charles, 23, and her 13-year-old twins, Nelson and Eddy.

Dion said she "did not take the time" to figure out her own health concerns. "I should have stopped."

Celine Dion talks stiff-person syndromeimpact on voice: 'Like somebody is strangling you'

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"My husband as well was fighting for his own life. I had to raise my kids. I had to hide. I had to try to be a hero. Feeling my body leaving me, holding onto my own dreams," she said of her private battle. "And the lying for me was … the burden was too much."

The "My Heart Will Go On" singer added that she could not handle "lying to the people who got me where I am today."

Stiff-person syndrome, or SPS, is a rare "neurological disorder with features of an autoimmune disease," the National Institute of Neurological Disorders and Stroke notes.

"It's a disease that's characterized by progressive muscle stiffness, muscle spasms, rigidity – typically in the muscles of the back, specifically the lower back, as well as the upper legs," Dr. Kunal Desai, a Yale Medicine neurologist and assistant professor of neurology who specializes in neuromuscular disease, previously told USA TODAY.

The disease causes "progressive muscle stiffness and painful spasms" that can be triggered by environmental factors such as "sudden movement, cold temperature or unexpected loud noises," Johns Hopkins Medicine said. 

Vogue France:Celine Dion talks accepting stiff person syndrome diagnosis, first meeting husband at 12

In another preview clip shared from the NBC interview on Friday, Dion said the diagnosis has had a significant impact on her voice.

"It's like somebody is strangling you," she told "Today" host Hoda Kotb in a preview of the interview. She added that when she tries to make her voice lower or higher, it results in a spasm.

The hourlong interview will air on NBC, her first televised interview since her diagnosis.

Dion is set to release a documentary that shows behind-the-scenes of her health battle later this month.

"I'm working hard every day, but I have to admit it's been a struggle," she said in the trailer, which sees her working toward being able to perform live again. "I miss it so much, the people. I miss them."

She continued: "If I can't run, I'll walk. If I can't walk, I'll crawl. But I won't stop."

Contributing: Taijuan Moorman