One piece of Star Wars trivia that fans may be unaware of is that John Lithgow voiced the role of Yoda in the radio drama versions of "The Empire Strikes Back" and "Return of the Jedi." In a 2017 appearance on “The Graham Norton Show,” the actor talked about how he got the role.
A year after “The Empire Strikes Back” was released, George Lucas developed the story into a radio series with Mark Hamill, Billy Dee Williams, and Anthony Daniels back to voice their respective characters. Frank Oz, however, did not return as Yoda.
John Madden, who directed the radio production was also directing Lithgow in a play at the time, and he shared with the actor that he was having a hard time finding the right person to voice Yoda. Lithgow recalled, “I said [in Yoda voice] Ohhhh! Impatient, is he? He hired me on the spot. It was the quickest job I've ever got."