 David Prowse (qv) only portrayed Darth Vader completely for the  first half of the movie. In the second half of the movie, the  character was played by Bob Anderson (III) (qv) (stuntman) during  the fight sequence, and Sebastian Shaw (I) (qv) after the  character is unmasked. James Earl Jones (qv) voiced the character  throughout, with the exception of the unmasking scene.