Noun
close harmony (uncountable)
A style of music where the chords are arranged within a narrow range, and the vocal styles of two or more singers either complement or are similar to each other.
The imprint will also release non choral recordings by current and former members of the College. citation The men of the choir, or choral scholars, also form their own close harmony group, The Gentlemen of St John's. Source: Internet
This is reflected in "When the Children Are Asleep", where the two sing in close harmony, but Enoch musically interrupts his intended's turn at the chorus with the words "Dreams that won't be interrupted". Source: Internet