Kenny Baker (b. 1934) is an actor best known for playing R2-D2 in all six Star Wars films. Although R2 made several Muppet related appearances, Baker did not perform the character: "On the few times that there was a Star Wars special they would use the three legged R2, like on The Muppet Show."
However, Baker did work with Jim Henson, as a member of the goblin corps in Labyrinth. His other films include Time Bandits, The Elephant Man, and Amadeus.