Several directors, most notably Guy Hamilton, and screenwriters (Mario Puzo, David and Leslie Newman, and Robert Benton) were associated with the project before Donner was hired to direct. Tom Mankiewicz was drafted in to rewrite the script and was given a "creative consultant" credit. It was decided to film both Superman and Superman II simultaneously, with Principal photography beginning in March 1977 and ending in October 1978. Tensions rose between Donner and the producers, and a decision was made to stop filming the sequel—of which 75 percent had already been completed—and finish the first film.