Simon told his partner, Art Garfunkel, that Garfunkel should sing it alone, the "white choirboy way", though Simon does add harmony on the final verse. Garfunkel felt it was not right for him; he liked Simon's falsetto on the demo and suggested that Simon sing. At the suggestion of Garfunkel and producer Roy Halee, Simon wrote an extra verse and a "bigger" ending, though he felt it was less cohesive with the earlier verses. The final verse was written about Simon's then-wife Peggy Harper, who had noticed her first gray hairs ("Sail on, silvergirl"). It does not refer to a drug abuser's hypodermic needle, as is sometimes claimed. The verse was Garfunkel's idea, but Simon reportedly did not like it.