Harry Nilsson appears as a character in Robert S. Levinson’s novel The John Lennon Affair. The book is a detective story featuring Neil Gulliver, a famous L.A. journalist who lives with (but is divorced from) soap star Stevie Marriner. The story shifts between events occurring right after John Lennon’s murder in 1980 and the events surround a 2000 Lennon tribute concert.
The character of "Harry Nilsson" is introduced early in the novel:
"John's dead," Harry said, "and to think that for all these years everyone thought it was Paul."
Author Bob Levinson knew Harry Nilsson – he met Harry when Harry was still working in a bank and writing songs on the side - and his association with the real Harry is described in the author’s notes at the end of the book.