Terry Southern of the Monty Python team. Cleese later described McGrath as having "no idea of comedy structure" and complained that the film ended up as "a series of celebrity walk-ons." The film was shot in London between February and May 1969. The cast was headed by Sellers (as Guy Grand) and Ringo Starr as his son Youngman Grand (a new character created for the movie), with cameo appearances by Spike Milligan, Christopher Lee, Laurence Harvey, Raquel Welch, Roman Polanski and Yul Brynner. As with "Dr Strangelove", Sellers habitually improvised on the script during filming. During production McGrath and Southern discussed a
Peter Sellers according to Sellers "a fantastic nightmare, part homosexual, part drug addict, part sadist". Kubrick encouraged Sellers to improvise and stated that he would often reach a "state of comic ecstasy". Kubrick had American jazz producer Norman Granz record portions of the script for Sellers to listen to, so he could study the voice and develop confidence, granting Sellers a free artistic licence. Sellers later claimed that his relationship with Kubrick became one of the most rewarding of his career. Writing in "The Sunday Times", Dilys Powell noted that Sellers gave "a firework performance, funny, malicious, only once for a few