I'll Be Your Sweetheart is a 1945 British historical musical film directed by Val Guest and starring Margaret Lockwood, Vic Oliver and Michael Rennie.

[2] Copyright scholar Adrian Johns has called the film "propaganda" and "a one-dimensional account of the piracy crisis [about sheet music in the early 20th century] from the publishers' perspective", but also highlighted its value as historical document, with large parts of the dialogue "closely culled from the actual raids, court cases, and arguments of 1900-1905.

He visits a music hall where he hears Edie Story singing "Oh Mr Porter" by George Le Brunn.

However, when composer Le Brunn dies impoverished, Edie makes an on-stage appeal to her audience to fight piracy.

[4][5] The 'biggest winners' at the box office in 1945 Britain were The Seventh Veil, with "runners up" being (in release order), Madonna of the Seven Moons, Old Acquaintance, Frenchman's Creek, Mrs Parkington, Arsenic and Old Lace, Meet Me in St Louis, A Song to Remember, Since You Went Away, Here Come the Waves, Tonight and Every Night, Hollywood Canteen, They Were Sisters, The Princess and the Pirate, The Adventures of Susan, National Velvet, Mrs Skefflington, I Live in Grosvenor Square, Nob Hill, Perfect Strangers, Valley of Decision, Conflict and Duffy's Tavern.

British "runners up" were They Were Sisters, I Live in Grosvenor Square, Perfect Strangers, Madonna of the Seven Moons, Waterloo Road, Blithe Spirit, The Way to the Stars, I'll Be Your Sweetheart, Dead of Night, Waltz Time and Henry V.[6] However Gainsborough Studios made no further musicals.