Island of Love (1963)

A con man named Steve Blair (Robert Preston), enlists an out-of-work, drunk writer Paul Ferris (Tony Randall) to write a fictitious screenplay he hopes will be funded by a rich, but unethical producer (who also happens to be a mobster) named Tony Dallas (Walter Matthau). As if that's not enough, Blair then plans to scam the money from Dallas, all with the beauty of a gorgeous Greek isle.