 According to TCM host Robert Osborne (II) (qv),  Paddy Chayefsky (qv) passed on having Walter Matthau (qv) or  Burt Lancaster (qv) in George C. Scott (qv)s role, and either  Jane Fonda (qv), Ali MacGraw (qv), or Candice Bergen (qv) in  Diana Rigg (qv)s.