Sufjan Stevens is learning how to walk again after being diagnosed with a rare nerve disorder.

The 48-year-old folk star woke up one day last month and found himself unable to walk and he was hospitalised and told he has Guillain-Barré syndrome, an autoimmune condition which causes rapid-onset muscle weakness.

As a result, Sufjan is unable to promote his upcoming album, 'Javelin,' which drops on October 6.

Giving a health update on Tumblr, he wrote: "Last month I woke up one morning and couldn’t walk.

"My hands, arms and legs were numb and tingling and I had no strength, no feeling, no mobility."

He continued: "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."

The Oscar and Grammy-nominated singer-songwriter has been treated by having immuno-hemoglobin infusions for five days.

However, they could only be administered if the disease hadn't gone to his brain, heart and lungs.

Sufjan was fortunate that it worked.

He went on: "Very scary, but it worked.

"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."

Now, the 'Mystery of Love' singer is focused on his slow and steady physical rehabilitation and hopes to be able to walk again within a year.

Sufjan added: "It’s a slow process, but they say I will ‘recover,’ it just takes a lot of time, patience, and hard work.

"Most people who have GBS learn to walk again on their own within a year, so I am hopeful."