Voicing Rowlf again in Die Muppets, he is one of only three remaining voice artists to reprise their Muppet Show roles that they originated; the other two being Christina Hoeltel as Scooter and Donald Arthur as Beauregard (and Uncle Deadly). Rüth's other dub credits, largely in animation, include the German voice of Winnie the Pooh in the recent films, Grandpa and Barney Gumble on The Simpsons, Mr. Garrison in South Park, various parts in the Asterix features, and two of John Ratzenberger's roles in Pixar films: Hamm in the Toy Story movies and P. T. Flea in A Bug's Life.