Hayes, 66, said he still has some difficulty with speech since the stroke a year ago. But he can still sing.
"I'm coming along good," he said.
In recent months, Hayes has been helping with the 50th anniversary events for Stax Records. He also has a new album coming out in September.
"It's about the old school, and some of the new school," he said. "Everything comes around again. It's going to be cool."
Hayes was the first black singer to win an Oscar for best original song for the theme from "Shaft" in 1972. While he had a string of hits, he is probably best known to younger people as the voice of Chef on "South Park."