- All-Star Cast: The Lincoln Center production with the New York Philharmonic sure is, featuring Neil Patrick Harris as Bobby, Patti LuPone as Joanne, Stephen Colbert as Harry, Anika Noni Rose as Marta, Christina Hendricks as April, Jon Cryer as David, Katie Finneran as Amy, Aaron Lazar as Paul, and Craig Bierko as Peter.
- Hey, It's That Guy! / Hey, It's That Voice!
- Merle Louise, who would go on to play the Beggar Woman and Cinderella's Mother, played Susan in the original production.
- Charles Kimbrough, who sings Harry on the original Broadway recording, might also be recognisable to Sondheim fans as Jules the art critic, or to Murphy Brown fans as Jim Dial.
- Doctor Horrible plays Bobby in one newer production.
- Mid Development Medium Shift: It was originally written by George Furth as a cycle of eleven short plays.