The play Beth (Mary Taylor Moore) and Calvin (Donald Sutherland) go to see at the theatre is Same Time, Next Year, a 1975 romantic comedy by Bernard Slade. The protagonists are a man (George) and a woman (Doris) who accidentally meet, have sex, and decide to meet every year at the same hotel for one weekend together. This goes on for 26 years.

During a conversation, they discuss Doris’ signature scent: it’s Lanvin My Sin [1].

This powdery musky fragrance was created by Madame Zed and launched in 1924.

[1] The Bernard Slade play was adapted into a film in 1978: it was directed by Robert Mulligan and starred Alan Alda and Ellen Burstyn. Here is my post about the same conversation in the film.