The Cure's 'Close to Me' was inspired by Robert Smith's childhood bout of chicken pox.
The 59-year-old singer added the lyrics to the 1985 track at the "last minute" as he wasn't sure the band had produced anything musically that would pair with the words he'd written about the sense of "impending doom" that had followed him for so many years.
He recalled: "At the last minute, I sang these words that I had left over. I didn't think there was anything musically that worked with the words.
"The words were actually about this sense of impending doom that I used to get.
"I had chicken pox when I was really young and it started there.
"I used to get these horrible, nightmarish visions of this head that used to hover in a chink of light that used to come when the bedroom lights were turned off and the door was just ajar.
"The shaft of light that came from the hallway used to illuminate this patch of wallpaper and it would come to life and prophesise doom to me through the night whenever I put my eyes in that general direction.
"And it came back to me when I was writing 'The Head On the Door' album. I was running myself into the ground a little bit and I started to suffer.
"I suddenly also started to get the same hallucinations, which was very odd.
"The song was essentially about those two things, but at the last minute I tried singing them over this jaunty bassline and drum pattern and it just clicked."
Over the years, Robert has grown to realise the song is actually much better than he originally thought.
He told Q magazine: "I always thought it relied entirely on the sound involved, the production, and a sense of claustrophobia, but in fact, when we did it acoustically, it's actually a jaunty little pop song. It's better than I think it is, probably."