Under director
Peter Glenville's guidance, he wrote the second
screenplay for the 1972 film version of
Man of La Mancha (1972), after the original creators of the show were fired from the film. When United
Artists discovered that Hopkins' screenplay removed most of the songs
from the film, he and Glenville were dismissed and
Arthur Hiller, who
subsequently re-hired original writer
Dale Wasserman to write the third
screenplay, was brought on as director.