Arguably, Prowse is most famous for playing the physical form of 
Darth Vader in the 
original Star Wars trilogy. Although he spoke the dialogue during the production of the films, 
James Earl Jones overdubbed the character's voice in post-production, a fact which Prowse bears some resentment for towards 
Star Wars creator 
George Lucas, since he was never told that his voice was not going to be used. However, Lucas claims he wanted a 'deeper voice' (Lucas has stated that Darth Vader had to have a deep, reverberating voice) that Prowse could not provide and never intended to use Prowse's voice. In the 2004 documentary, 
Empire of Dreams, actress 
Carrie Fisher, who played 
Princess Leia Organa in the original trilogy films, quipped that they nicknamed Prowse "Darth Farmer" because of his un-intimidating 
West Country accent.
 To Prowse, the most annoying incident came during the filming of 
The Empire Strikes Back. The major plot twist in 
Empire is the revelation of who 
Luke Skywalker's father is. In 
Star Wars Episode IV: A New Hope, Skywalker is told by 
Obi-Wan Kenobi that his father was betrayed and murdered by a young pupil named Darth Vader. However, in 
Empire, Vader himself reveals that he is actually Skywalker's father. According to 
Empire director 
Irvin Kershner, the shooting script had a false page with Vader's dialogue implicating Kenobi as the murderer of Luke's father, but at the time, only he and producer 
Gary Kurtz were privy to the knowledge that Darth Vader and Luke's father were the same person. Moments before the scene was filmed, 
Mark Hamill, the actor playing Luke, was taken aside privately and told the truth by Kershner, who encouraged him to ignore the dialogue Prowse was speaking and "use your own rhythm compared to what he's doing." In later years, Prowse claimed he would sometimes deliver joke versions of his lines in 
Empire and 
Return of the Jedi.
 Prowse lobbied to be included in 
Star Wars Episode III: Revenge of the Sith, reprising his role as the fully-armored Darth Vader, but his requests fell on deaf ears. 
Hayden Christensen, who played 
Anakin Skywalker in 
Episode III as well as its predecessor, 
Star Wars Episode II: Attack of the Clones, says he begged Lucas to have the costume designers build a suit that would fit him despite the fact that he is fully five inches shorter than Prowse.
 Prowse continues to associate himself with his role in the 
Star Wars films and is involved in the convention circuit. Despite this, he has not been included in recent reunions of the original cast, such as those for the 
Empire of Dreams documentary and the 2005 
Vanity Fair cover.
 Recently he played a small cameo role in Star Wars fanfilms Order of the Sith: Vengeance and its sequel Downfall - 
Order of the Sith - alongside 
Jeremy Bulloch and 
Michael Sheard. These fanfilms were made in England in support of Save the Children.