"Unforeseen and serious medical issues" have prompted John Anderson to cancel a headlining festival appearance scheduled for Saturday (Aug. 5).

On Tuesday (Aug. 1), organizers of the Main Street Music Festival in Albertville, Ala., revealed via Facebook that, that morning, they had been notified that Anderson needed to cancel his Saturday night show because of medical trouble.

"He will remain, for the time being, under the direct care and supervision of a Nashville-area doctor," a statement from Anderson's team, shared by the Main Street Music Festival, reads. "John is deeply saddened to not be able to perform for his friends in Alabama, and hopeful he will begin healing soon.”

In place of Anderson, Main Street Music Festival organizers added Craig Morgan to the event's lineup; festival staff also offered get-well-soon wishes to Anderson via the Facebook post. Anderson himself has yet to comment on the details of his illness or his show's cancellation.

Anderson, a Nashville Songwriters Hall of Fame inductee, is known for hits such as "Black Sheep," "Money in the Bank" and more; he's charted more than 40 singles since debuting in country music in the late 1970s and has five No. 1 hits.

Anderson's most recent album, Goldmine, was released in 2015. It was Anderson’s first album in nine years, a response to demand from his dedicated fans.

“We did have a record, actually a couple records, but they never got released, so therefore, our fans have been wondering, ‘Are you all going to make any more music?’ or ‘Do you still sing?’” Anderson told The Boot when Goldmine was released. “This particular record, after those kind of dismal attempts of our last few, I wanted to try and be sure we could at least be set up where the fans would know about it when we did make a record.”