Emperor Palpatine was first shown in Ep. V – The Empire Strikes Back in 1980. This was before Ian McDiarmid was cast to play the character in Return of the Jedi and the prequel trilogy. Instead, makeup director Rick Baker dressed up his wife, Elaine Baker, for the part.
In post-production, a chimpanzee’s eyes were superimposed onto Mrs. Baker’s face to make the appearance of the Emperor more unsettling. The voice was provided by a man, veteran voice actor Clive Revill. The scene was later re-shot with McDiarmid and some slightly different dialog for the DVD release, so your best bet to see the original “woman with chimp eyes” Emperor would be on VHS or YouTube.
via omg-facts