titular line

The titular line (or title line) is a line in a film, book or song which includes the name of the film, book or song.

eg. In the movie "Limitless" starring Bradley Cooper, the protagonist (Eddie Morra) explains the effect that a newfound mystery pill has on his intellect. He says, "a tablet a day, and what I can do with my day was limitless." This is called a titular line.