[Where have I heard this before?]

Well...just slightly off the topic - but another film Grant was offered was Arabesque... According to an interview with Gregory Peck the whole Sophia Loren - Cary Grant thing became problematic and Grant turned it down.  Peck complained that it was fine for Grant - but that chase through the cornfield became a real issue for Peck, as Grant was in better shape and Peck had arthritis...

[Characters Mentioned but Never Seen]

I don't know if "he" is a character ...but how about Max, the mystery lover from Witness for the Prosecution?