Paul McCartney was offered Shrdlu, as was Alan Bennett.
Ringo Starr was sought in vain for a major role.
Billie Whitelaw was cast after seven high profile US leading ladies passed.
Joe Mantell was offered a key role.
Topol was offered a major role.
Patricia Phoenix was on the shortlist for Mrs Zero.
Muhammad Ali was suggested for Lt. Charles.
According to the director of this film Jerome Epstein, it was the idea of comedian Charles Chaplin to portray the scenes in Heaven the way they turned out in the film, with hot dog stands among other things.
In 1967 Richard Widmark was announced for the lead.
When this was set up at Seven Arts in 1964, Art Carney, Martin Balsam and Shelley Winters were in negotiations to star.