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 was universally lauded by critics and is considered by critic Danny Smith to be the "crowning triumph of Peter Sellers's remarkable career". Critic Frank Rich wrote that the acting skill required for this sort of role, with a "schismatic personality that Peter had to convey with strenuous vocal and gestural technique ... A lesser actor would have made the character's mental dysfunction flamboyant and drastic ... [His] intelligence was always deeper, his onscreen confidence greater, his technique much more finely honed": in achieving this, Sellers "makes the film's fantastic premise credible". The film earned Sellers a Best Actor award at