This ultimately led to James Earl Jones being brought in to voice the character.
Prowse went onto play the character in A New Hope, The Empire Strikes Back, and Return of the Jedi.
Lucas believed he would be the perfect person to portray the physical form of Darth Vader but thought his West Country accent wouldn’t match the character.
He was originally promised that he would be seen and heard at the end of Jedi, but actor Sebastian Stan was ultimately utilized.