On February 6, 2015, Paramount Pictures and New Regency announced that Robert Zemeckis was to direct an untitled World War II romantic thriller, in which Brad Pitt would star.[3] Steven Knight wrote the original script, in development by Graham King's GK Films, which now would be produced by ImageMovers' Zemeckis and Steve Starkey along with King.[7] On June 8, 2015, Marion Cotillard was cast to play a spy along with Pitt, who fall in love during a mission to kill a German official.[4] In August 2015, Knight said that the film would be based on a true story told to him at the age of 21, and also that the shooting would start in January 2016.[8] On January 28, 2016, Jared Harris joined the film.[5] On March 8, 2016, Lizzy Caplan was cast to play Pitt's sister.[6] Executive producers on the film would be Knight, Jack Rapke, Patrick McCormick and Denis O'Sullivan.[6] Alan Silvestri composed the music.[9]