Which comedian made an appearance in Charlie Chaplin's film 'Limelight'?

Limelight is a 1952 comedy-drama film written, produced, and directed by Charlie Chaplin. Unlike his earlier films, the score was composed by Chaplin and arranged by Ray Rasch, marking this as the first film that he did not musically arrange.

The film stars Chaplin as a washed-up comedian who saves a suicidal dancer from killing herself, played by Claire Bloom, and both try to get through life. Additional roles are provided by Nigel Bruce, Sydney Chaplin as Sydney Earl Chaplin, Wheeler Dryden, and Norman Lloyd with an appearance from Buster Keaton. In dance scenes, Bloom is doubled by Melissa Hayden.

Joseph Frank "Buster" Keaton (October 4, 1895 – February 1, 1966) was an American actor, comedian, film director, producer, screenwriter, and stunt performer. He was best known for his silent films, in which his trademark was physical comedy with a consistently stoic, deadpan expression, earning him the nickname "The Great Stone Face."