Indie songwriter Sufjan Stevens announced that he is relearning how to walk after being diagnosed with Guillain-Barré syndrome, a rare autoimmune disease.

Stevens — whose first name is pronounced SOOF-yawn — announced the news in a Tumblr post. The 48-year-old singer-songwriter explained why he was unable to promote his newest album "Javelin", which is set to be released Oct. 6.

"Last month I woke up one morning and couldn’t walk," the "Chicago" singer wrote in a post. "My hands, arms and legs were numb and tingling and I had no strength, no feeling, no mobility."

"My brother drove me to the ER and after a series of tests — MRIs, EMGs, cat scans, X-rays, spinal taps (!), echo-cardiograms, etc. — the neurologists diagnosed me with an autoimmune disorder called Guillian-Barre Syndrome," he added.

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Stevens explained that the disease can be treated by administering immuno-hemoglobin infusions for five days, as long as the disease doesn't reach the brain, heart and lungs.

"Very scary, but it worked," Stevens wrote. "I spent about two weeks in Med/Surg, stuck in a bed, while my doctors did all the things to keep me alive and stabilize my condition. I owe them my life."

The singer was transferred into an acute rehabilitation center on Sept. 8, where he is learning how to walk through intensive physical and occupational therapy. 

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"It’s a slow process, but they say I will ‘recover,’ it just takes a lot of time, patience, and hard work," Stevens wrote. "Most people who have GBS learn to walk again on their own within a year, so I am hopeful."

Stevens is best known for his song "Mystery of Love", which was written for the 2017 film "Call Me By Your Name". His albums "Illinois" and "Carrie & Lowell" were both met with critical acclaim.

"Mystery of Love" was nominated for both an Oscar and a Grammy.

The Associated Press contributed to this report.