Hansel is diabetic as a result of his experience in the gingerbread house as a child. In the original script, Gretel was also supposed to have an eating disorder as a result of the same trauma, but this was not included in the movie. Insulin hadn't been invented yet.
Originally scheduled for release in March 2012, the movie was delayed for ten months to accommodate Jeremy Renner's appearances in Avengers (2012) and Jason Bourne : L'Héritage (2012), and to give director Tommy Wirkola time to shoot a post-credits scene.
Despite portraying a brother and sister close in age, Jeremy Renner is 15 years older than Gemma Arterton.
Jeremy Renner and Gemma Arterton had a month of training beforehand to prepare for the physical demands of their roles.
Director Tommy Wirkola got the idea to create the film, based on the adult lives of Hansel and Gretel in 2007, while at film school in Australia. After being discovered by Gary Sanchez Productions, Wirkola pitched the idea at a meeting with Paramount Pictures and won a contract.