From Wikipedia, the free encyclopedia. Kathryn "Kathy" Mullen is an actress, voice actress, and puppeteer most closely associated with Jim Henson projects. She began performing on The Muppet Show in its third season, primarily as Gaffer the Backstage Cat. She also voice directed Dog City for Nelvana, worked as a designer for The Muppet Movie, a performing assistant for Yoda on The Empire Strikes Back, and was one of the creators of Between the Lions. While reprising this character for several M...