Eleanor Audley
Eleanor Audley (November 19, 1905 – November 25, 1991) was an American actress who was a familiar radio and animation voice, in addition to her TV and film roles. She is best remembered on television as Eunice Douglas on Green Acres and, for many, for providing Disney animated features with their most outstanding and memorable villainess voices, most notably two of the most sinister Disney villainesses, Lady Tremaine and Maleficent.
Description above from the Wikipedia article Bernard Lee, licensed under CC-BY-SA, full list of contributors on Wikipedia.
