The Man Who Killed Don Quixote is the story of an advertising executive who meets a modern day incarnation of Don Quixote, and is dragged through a series of adventures.
Gilliam first began pre-production in 1998, casting Johnny Depp as the leading man.
Filming began in 2000, however just a few days in a series of disasters including sudden illness and a freak storm, halted the production in its tracks, and to date it has never resumed.
This was all chronicled in the documentary Lost in La Mancha, which was made by a crew originally hired to film the production for a DVD special feature.
Depp is no longer involved in the production, instead Adam Driver will play the role.
The film is expected to be released in 2018.