The Emperor was almost played by a different actor in Return of the Jedi, and it would have changed Star Wars moving forward. While mentioned in the original film, the Emperor did not appear onscreen until The Empire Strikes Back, where he communicated with Darth Vader via hologram. In the 1980 theatrical cut of the movie, the character was physically portrayed by Marjorie Eaton, and Clive Revill performed the voice. With the Emperor set to have a larger role in the flesh during Return of the Jedi's third act, the decision was made to cast somebody as the character. As many fans know, the job fell to Ian McDiarmid.
McDiarmid is now as integral a part of the Star Wars legacy as Mark Hamill, Harrison Ford, and Carrie Fisher. He's reprised the role multiple times, most notably in the three prequel films and a surprise return in this December's Star Wars: The Rise of Skywalker. It's impossible to imagine anyone besides McDiarmid playing the galaxy's ultimate evil, but that almost happened in the original trilogy. As perfect as he proved to be for the part, McDiarmid was not the first choice.
Alan Webb Almost Played the Emperor
During pre-production on Return of the Jedi, George Lucas, director Richard Marquand, and others on the creative team couldn't decide if the Emperor should be played by an older thespian or a younger actor. Per J.W. Rinzler's 2013 book, The Making of Return of the Jedi, Marquand eventually talked himself into the former because he felt an old man would have "qualities and characteristics that a young man couldn't possibly have." Out of the several who auditioned, 75-year old Alan Webb was cast. According to the book, Webb got the gig in part because Lindsay Anderson, who was also in the running, had to pass because of his commitment to Britannia Hospital.
Webb was an English stage and film actor with several credits to his name, including The Great Train Robbery, The Duelists, and The Taming of the Shrew. Unfortunately, he never got the opportunity to act in Star Wars. A combination of a horrible English snowstorm and Webb catching the flu prevented him from traveling to the set. He then stepped down from the project, explaining in a letter to Marquand he "felt that the part was too big for him." Shortly after, in June 1982, Webb passed away. When hiring a new Emperor actor, Marquand went in the opposite direction and cast the then 37-year old McDiarmid, who would obviously be playing a character much older than him. Marquand and Lucas were counting on McDiarmid to carry the role.
How Ian McDiarmid Influenced The Emperor
After being cast, McDiarmid immediately made his imprint on the role. Originally, the plan for Return of the Jedi was to overdub the Emperor's voice (like what happened in Empire). Marquand actually told McDiarmid that if the actor could get his voice close to Revill's he may be allowed to keep it. This development surprised McDiarmid, who felt the Emperor should sound different than the previous film. He argued to Marquand that at the time, Revill "didn't really know the character he was playing" and completed his work in quick fashion. Upon seeing what the Emperor looked like, McDiarmid was inspired to craft a voice that sounded like "English upper class and trying to sound like a toad." Evidently, Lucas liked the voice (which became a defining characteristic of the Emperor), and McDiarmid was allowed to keep it.
From the beginning, McDiarmid was clearly passionate about the role and he has relished in playing the Emperor ever since. One only has to look at his devilishly hammy "Roll it AGAIN!" line at Celebration Chicago to see how much he enjoys it. In an interview, McDiarmid went on record to say he doesn't want anyone else playing the Emperor. This quote was given a few years ago, well after the prequels had concluded. Basically, he was saying if Palpatine were ever to return for one of the new films (which, of course, is exactly what happened), he would want to play him. McDiarmid had felt an ownership and pride over the role that another actor may not have. Lucas and company got extraordinarily lucky with McDiarmid. Not every Star Wars vet is eager to jump back into the well.
How Webb's Emperor Would Have Impacted Star Wars Long-Term
If Webb had been able to play the Emperor, it probably wouldn't have caused too many changes to the overall Skywalker saga narrative. Any version of the prequels needs Palpatine playing a major role; he's the one who formed the Galactic Empire and turned Anakin Skywalker to the dark side. Much like Obi-Wan, Palpatine had to be a main character in the prequels. Obviously, if Webb was in Jedi, the role would need to be recast for Lucas' second trilogy. Webb would have been in his early 90s if he was alive during production of The Phantom Menace, which would have put him out of the running. Perhaps McDiarmid, who was in his 50s when Menace came out, would have landed the role. After all, he did come in for a casting interview on Jedi, and Lucas may have remembered him when it was time to make the prequels.
As for the sequel trilogy, that's more difficult to say. According to Kathleen Kennedy, it was always the plan to use the Emperor in Episode IX and have him be the villain that tied the entire saga together. He is the overarching big bad of the story. Would Lucasfilm have gone in another direction if they didn't have McDiarmid a phone call away? At the very least, there's the possibility the role would have been recast again for The Rise of Skywalker, depending on who was brought in for the prequels. Considering those films' mixed receptions, not every prequel era actor is jumping at the chance to return. Ewan McGregor repeatedly said he's game to come back as Obi-Wan, but his co-star Hayden Christensen is content to remain out of the spotlight. Luckily, McDiarmid is passionate about the character and the material, which made this easy on J.J. Abrams and crew. They wanted to have Palpatine in the movie and knew the only man to play him would love another crack at it.
