Written and directed by playwright Terry Johnson, the film tells the story of the working and personal relationship between the comedians Peter Cook and Dudley Moore, a hugely popular duo in the UK during the 1960s and 1970s. Focusing primarily on Cook, the film traces the pair from their first meeting through their career as part of the Beyond the Fringe review, their television series Not Only... But Also (from which the film takes its title) and various other projects before their later estrangement as Moore became a successful Hollywood film star and Cook remained in the UK. Although some events are fictionalised and condensed, and the film was criticised in some quarters for an unsympathetic portrayal of many of Cook's faults, it was generally well-received critically.