For her few scenes with Michael Caine, Shelley Winters couldn't understand his dialogue at all due to his strong Cockney accent and had to wait until her leading man stopped moving his lips before responding with her lines.
On its original release, the film had an all instrumental soundtrack, by Sonny Rollins. The Oscar nominated song, by Burt Bacharach and Hal David, was added for the American release, and to a British re-release. For the UK re-release, the song was sung by Cilla Black over the end credits, which went to #9 on the British charts. For the US release, the song was originally to be sung by Dionne Warwick over the end credits, but was replaced at the last minute by the version sung by Cher. Ironically, Warwick's version outperformed Cher's on the Billboard charts. Burt Bacharach produced Cilla's version, although George Martin insisted his be the only name to be credited.
A rarity in film, Michael Caine's character sporadically engages the cinema audience by looking straight into the camera as he voices his thoughts, a technique called "breaking the fourth wall". Curiously enough, the film's director Lewis Gilbert went on to direct Pauline Collins as the titular Shirley Valentine (1989) in which she also spoke her thoughts directly to the viewer.