Actress Selma Blair had a reason to smile at Discovery+'s Television Critics Association panel for her upcoming documentary "Introducing, Selma Blair," she's in remission from multiple sclerosis.

"My prognosis is great," the former "Cruel Intentions" star said. "Stem cell [treatments] put me in remission. It took about a year after stem cells for the inflammation and lesions to really go down."

Blair, 49, had undergone chemotherapy and a stem cell transplant to essentially "reboot" her nervous system, she said.

The actress also said that she had been feeling much better of late, but didn't want to rush to make headlines. "I was reluctant to talk about it because I felt this need to be more healed and more fixed," Blair said.

"I've accrued a lifetime of some baggage in the brain that still needs a little sorting out or accepting," the actress continued. "That took me a minute to get to that acceptance."

"I have really felt unwell and misunderstood for so long that it's just, me," she added.

Blair revealed her diagnosis in 2018, later telling ABC News' Robin Roberts that she felt "relief" after she finally learned why she'd been suffering years of crippling pain and other physical symptoms.

"I was really struggling with, 'How am I gonna get by in life?'" she recalled. "And [being] not taken seriously by doctors, just, 'Single mother, you're exhausted, financial burden, blah, blah, blah.'"

"And so when I got the diagnosis, I cried with some relief. Like, 'Oh, good, I'll be able to do something," she said.

MS is a disease of the central nervous system, according to The Mayo Clinic. It’s estimated that one million people in the U.S. and nearly 2.1 million people worldwide are affected by the disease. Symptoms can run the gamut, according to Dr. Jennifer Ashton, ABC News' chief medical correspondent.

"People can complain of a squeezing sensation in their torso, fatigue, weakness, difficulty walking, stiffness or muscle spasms, loss of balance," she said. "This can affect speech, it can affect vision. It can affect bladder function. This is a debilitating and often progressive neurologic condition so the symptoms really vary."

"Introducing Selma Blair," which catalogs her life with multiple sclerosis and her struggles with her treatment, opens in theaters Oct. 15 and streams on discovery+ on Oct. 21.