1940s comedy in which an ordinary Brit steps into the shoes of one of the world's biggest opera stars. George Butters (George Formby) happens to look uncannily like the celebrated South American tenor, Gilli Vannetti (also Formby). When Gilli disappears, George is invited to pass himself off as the singer so that the show can go on. That George can't sing particularly well is the least of his worries. A pair of hitmen, Swiftly (Ronald Shiner) and Slappy (Alf Goddard), are in pursuit of Vannetti and are unaware of the switch in identities. There is also the matter of the tenor's personal assistant, Carole (Linden Travers), with whom George falls hopelessly in love. Thrown in at the deep end, George has little choice but to try and convince in the role.