"Nature Boy" is a 1948 song first recorded by American singer Nat King Cole. It helped launch his career to a wider audience, especially the white music market.
It appears on the first soundtrack as a studio version performed by English singer David Bowie and towards the end a remixed version by Bowie and the group Massive Attack is played. An orchestral version mixed with the track 'Ascension' appears on the second soundtrack.
Use in the film
It is heard in the opening scene, sung by John Leguizamo as his character Toulouse and the line "the greatest thing you'll ever learn is just to love and be loved in return" is a recurring theme throughout and in the closing scene along with Ewan McGregor as Christian delivering the last line.
The remix by Massive Attack is played on the DVD main menu.