Anthony Hopkins had previously portrayed C.S. Lewis in Terra das Sombras (1993) 30 years prior to this film.
The waltz, called "And the Waltz Goes On" that is played right before the end cards was composed by Anthony Hopkins.
Somewhat late in this film, Lewis says to Freud (played in this film by Anthony Hopkins) "What if God wants to perfect us through suffering? Make us realize that real happiness, eternal happiness, can only come through him? If pleasure is his whisper, pain is his megaphone." In the 1993 film Terra das Sombras (1993) in which actor Hopkiins plays C.S. Lewis, quite early in the film, Lewis says in a radio broadcast " I suggest to you that it is because God loves us that He makes us the gift of suffering. To put it another way, pain is God's megaphone to rouse a deaf world."
The closing credits have multiple title cards explaining things that happened to both Lewis and Freud after the events of this film. They mention that during World War II, Lewis housed children being evacuated from London during the Nazi air raids. They do not mention that one of these was Jill Flewett, who later married a grandson of Sigmund Freud, Clement Freud.
The film based on the stage play of the same name by Mark St. Germain, which is in turn based upon the non-fiction book "The Question of God" by Armand Nicholi. The book also inspired a non-fiction documentary by that name on PBS. The book and documentary compare the lives and ideas of Lewis and Freud but unlike the play and this film do not postulate an imaginary meeting of the two men.
The play is simply confined to their conversation, while the film expands the play by showing scenes from the outside personal lives of Lewis and Freud.