southern attended the cannes film festival in the spring of 1966, where he met andy warhol and gerard malanga, and he remained in touch with malanga for many years. on his return to london he continued work on the "casino royale" screenplay and a screen adaptation of "the magic christian" for peter sellers, who was planning his film version. sandy lieberson optioned southern's first novel "flash and filigree" and united artists optioned "candy". michael cooper also introduced southern to the anthony burgess novel "a clockwork orange", and southern later encouraged stanley kubrick to make his film version of the book after mgm refused to back kubrick's planned film on napoleon. southern and cooper then began to plan their own film adaptation of the novel, to star mick jagger and the rolling stones as alex and his gang of droogs.