Sufjan Stevens, the singer-songwriter behind the local road-trip anthem “Chicago,” says he’s relearning how to walk after being treated for Guillian-Barre Syndrome.

In a post on his website, the 48-year-old musician says he been in a hospital and in physical rehab since waking up one morning last month with no ability to walk.

“My hands, arms and legs were numb and tingling and I had no strength, no feeling, no mobility,” he wrote.

Neurologists diagnosed him with the autoimmune disorder and for five days treated him with immuno-hemoglobin infusions. “Very scary,” Stevens wrote, “but it worked.”

He said he’s been “undergoing intensive physical therapy/occupational therapy” since Sept. 8.

Stevens’ rich body of work includes the 2005 album “Illinois,” which includes the popular song “Chicago” and references other elements of the state’s history and geography in its lyrics.

A new stage presentation based on the album had a sold-out world premiere over the summer at Bard College in New York State’s Hudson Valley and is scheduled to make its local premiere at Chicago Shakespeare Theatre in January.

“I couldn’t tell you if it’s a concert or dance-theater piece or musical,” director and co-writer Justin Peck told Pitchfork in June. “It’s somewhere amidst all that but feels like its own thing.”

Stevens’ 10th studio album, “Javelin,” is set for release Oct. 6.

His song “Mystery of Love,” written for the 2017 film “Call Me by Your Name,” was nominated for both a Grammy and an Oscar.