During the scene when Chaplin is at work on Shoulder Arms (1918) he asks his cameraman Roland Totheroh how the light is. Totheroh (and the rest of the crew) replies 'better down at Barney's bar'. This was the signal for production to end for the day - the 'light' Chaplin was referring to was the light beer served at Barney Oldfield's bar, which was the favourite drink and hangout for the crew after filming.
In an interview on Inside the Actor's Studio, Robert Downey Jr. said that while preparing for the movie he watched all of Charlie Chaplin's movies. When asked what how he felt about them he said, "They scared the hell out of me."
Originally called "Charlie", as he was known among his friends and family. The makers of the Cliff Robertson movie Charly (1968). complained that the title would lead to confusion with their movie, so the film had to be renamed to "Chaplin".
Kevin Kline was originally considered by Richard Attenborough to play Chaplin. Kline originally turned down the role of Douglas Fairbanks because his child had just been born. Attenborough agreed to delay the shooting of Kline's scenes for a month.
Director Richard Attenborough turned down many film roles because of obligations to the pictures he had directed. Due to the post-production and promotion of this film, he almost had to do so again when Steven Spielberg offered him the role of John Hammond in Jurassic Park (1993). However, unlike many other film directors, Spielberg offered to move his production schedule to accommodate Attenborough.
When Chaplin arrives in Hollywood (to join Mack Sennett) a film is being made. Chaplin joins in and improvises a complex scene. This is actually the final chase sequence from The Adventurer (1917). The location for the last shots of the opening sequence of the same film are used when Chaplin takes Oona Chaplin on a tour of his old haunts just before they leave for Europe.
Bryan Forbes's discarded script had a different beginning and focused on some darker elements of Chaplin's life and personality. Although his script was not used, the WGA ruled that Forbes got writing credit because much of the film's framework was derived from his script.
Although Roland Totheroh is depicted in this film to have worked with Chaplin at Keystone in 1914, it was not until a year later that the two began their working relationship that was to last 37 years from 1915 until Chaplin was exiled from the United States in 1952.