Shortly after skyrocketing to success in 1914 with Keystone studios, Charles Chaplin made a brief foray into the music business, self-publishing a number of popular tunes.
While this venture was only a limited success, Chaplin's interest in music continued unabated, despite having minimal formal training in composition or on his chosen instrument, the cello. Once he had his own studio and creative control over his films, Chaplin employed arrangers to work his own musical ideas into full scores.
As with the Marx Brothers, however, Chaplin's musical proficiency shouldn't be surprising, as Chaplin also came out of a variety show tradition in which performers were expected to be multi-instrumentalists. All the same, it was rather unusual that Chaplin played the cello left-handed, something he never bothered to "correct."