Harpo Marx York accent his entire life. According to those who personally knew him, Harpo's voice was much deeper than Groucho's, but it also sounded very similar to Chico's. His son, Bill, recalled that in private Harpo had a very deep and mature soft-spoken voice, but that he was "not verbose" like the other Marx brothers; Harpo preferred listening and learning from others. Harpo's final public appearance came on January 19, 1963 with singer/comedian Allan Sherman. Sherman burst into tears when Harpo announced his retirement from the entertainment business. Comedian Steve Allen, who was in the audience, remembered that Harpo spoke for
Marx Brothers one day after heart surgery. In 1966 Filmation produced a pilot for a Marx Brothers cartoon. Groucho's voice was supplied by Pat Harrington Jr. and other voices were done by Ted Knight and Joe Besser. In 1970, the four Marx Brothers had a brief reunion of sorts in the animated ABC television special "The Mad, Mad, Mad Comedians", produced by Rankin-Bass animation (of "Rudolph the Red-Nosed Reindeer" fame). The special featured animated reworkings of various famous comedians' acts, including W. C. Fields, Jack Benny, George Burns, Henny Youngman, the Smothers Brothers, Flip Wilson, Phyllis Diller, Jack E. Leonard, George Jessel