Ella Mitchell (1937-2024) was a gospel singer and actress who appeared on Sesame Street twice in season 4. She sings four songs in Episode 0487 (where Oscar the Grouch riffs on one of them) and two songs in Episode 0532 including "The Gospel Alphabet".
On Broadway, Mitchell took over from Mabel King as Evillene in The Wiz. Her other credits include the 2000 film Big Momma's House (appearing briefly in the title role, otherwise impersonated by Martin Lawrence).