Although the film was made and released in 1944 during the Second World War, it takes place three years after the end of the war in peacetime Britain.
Diana Dors was screen-tested for Heidi. It wasn't the only time Jean Simmons was chosen over her.. She also lost the roles of Young Estella in Great Expectations (1946), Kanchi in Black Narcissus (1947) and Emmeline in The Blue Lagoon (1949) to Simmons.
In the film, Nina, Margaret Lockwood's character, does a self-referential quote to the 1942 film Casablanca (1942). In reality, Lockwood was considered for the lead role before Ingrid Bergman was cast.
Both Margaret Lockwood and Jean Simmons would later appear in Hungry Hill (1947). Simmons would subsequently star in a long-gestating project that at one point was earmarked for Lockwood, The Blue Lagoon (1949).