Both described the powerful instant attraction, but both were also married – June to singer Carl Smith and then Edwin Lee Nix, and Johnny to his teenage sweetheart Vivian Liberto.

At the time however, there was more speculation over June’s relationship with Elvis. He was, of course, notoriously linked with women he worked with throughout his career, as well as fans in every city he visited.

In 2008, June’s son John Carter Cash released the biography Anchored In Love: An Intimate Portrait of June Carter Cash with his own insight into the stars’ relationship.

He wrote: “Throughout my life, I would see Mom get a mischievous twinkle in her eye whenever she mentioned Elvis Presley. Her eyes would flash merrily, and she would say, ‘You know, son, your father was always jealous of Elvis.’