NEW YORK (AP) — A representative for Roberta Flack announced Monday that the Grammy-winning musician has ALS, commonly known as Lou Gehrig's disease, and can no longer sing.

The progressive disease "has made it impossible to sing and not easy to speak," Flack's manager Suzanne Koga said in a release. "But it will take a lot more than ALS to silence this icon."

The announcement of the amyotrophic lateral sclerosis diagnosis comes just ahead of the premiere of "Roberta," a feature-length documentary debuting Thursday at the DOCNYC film festival.

Flack is known for hits like "Killing Me Softly Wi...