The song was originally recorded by Jamaican reggae star Half Pint with the title of "Winsome." It was a big hit and his first #1 in his home country. Half Pint heard about the Stones covering his song from percussionist Sydney Wolfe who was at a studio in Holland when Keith Richards chose it. Wolfe relayed the news to Half Pint about the re-titled rock version.
The Jamaican reggae star surmised in The Sunday Gleaner: "He (Richards) used to spend a lot of time in Jamaica. He probably was around when it was popular on the charts."
Half Pint added: "They did it in a slow tempo way. That tempo was more like a ballad tempo, but you can hear the rock attitude. They had rock with a pop feel."
He concluded that the song's reggae origins were not forgotten and the Stones also "did it in a way that you can realize it was a reggae song. It was not far from reggae, but you could hear the difference."
Keith Richards sang on this with reggae star Jimmy Cliff. Cliff had a hit years later with "I Can See Clearly Now."
It really was so easy for Linda Ronstadt to score a hit with her Buddy Holly cover of "It's So Easy." She would sometimes change the lyric to: "It's so easy to have a hit, all you have to do is recycle it."