The history of this classic romantic ballad is a long and complicated one, involving two English folk singers, an American schoolteacher, a screen legend – and a dead cat.

The first time ever I heard this song, like most others at the the time, was when it was featured in a love scene in Clint Eastwood’s 1971 film Play Misty For Me. The second time was a year later when it was released as a single and became a hit – perhaps the slowest hit single of all time – for Roberta Flack.

But the song’s history goes way back further. All the way to 1957, in fact, when it was written by an Englishman, the legendary political folk singer Ewan MacColl for his lover and future wife, Peggy Seeger. He supposedly sang it down the telephone to her the first time, then sent her a tape to hear when she was alone and he was with his wife.

Peggy sang it in folk clubs up and down the land before it found its way across the Atlantic, where it was popularised by an American folk group called The Kingston Trio and others including Peter, Paul & Mary and a gospel-folk duo called Joe & Eddie.

Their version caught the ear of a young black schoolteacher called Roberta Flack, perhaps because one of the duo was also African-American, and she taught it to her school choir in Washington DC.

She also included it in her set-list when she began a singing residency at a DC nightclub, and recorded her emotional slowed-down version – at more than five minutes, it’s twice the length of Seeger’s original – two days after returning from her first ever out-of-town engagement, in Detroit, having come home to find her pet cat had been run over and killed while she was away.

That is where the emotion in her performance is coming from.

Anyway, Clint Eastwood heard her version, included on her debut album, on his car radio while driving down an LA freeway and called her up to ask if he could use it in his upcoming film about a disc jockey and a stalker. Roberta jumped at the chance, and the $2,000 fee, but said she would like to re-record it as it was “too slow”. Clint, never a man of many words, responded: “No it’s not.”

The film was a hit, the song (shortened by a minute) became a hit, and the rest was history, though MacColl famously hated all the cover versions, especially Elvis’s, deeming them to be “travesties – bludgeoning, histrionic and lacking in grace.”