Knnillssonn is the fourteenth album by Harry Nilsson. This album was Nilsson's personal favorite while recording it, as his voice had recovered from the Pussy Cats sessions, his songs were developed and his singing was in top form. RCA agreed and had prepared to promote the album heavily as a comeback album after his previous efforts were mostly missed by the public. Shortly after the album was released however, Elvis Presley died and RCA shifted their focus, abandoning Nilsson and many other artists in its wake.
Klaus Voorman, billed on the album as Mara Gibb was the "guest mystery singer" on "Perfect Day." St. Paul's Cathedral Choir Boys choir are also on this track in addition to "All I Think About Is You."