Les Jones

A&E > John Hartford and Johnny Cash at the Grand Ole Opry

And I think that's Vassar Clements on the fiddle during "Uncle Pen," a song he also played with Old and In the Way.

In John Hartford trivia:

In 1967, Hartford's second album Earthwords & Music spawned his first major hit, "Gentle On My Mind." His recording of the song was only a modest success, but it caught the notice of Glen Campbell, who recorded his own version, which gave the song much wider publication. At the 1968 Grammies, the song netted four awards, two of which went to Hartford; just as importantly, it became one of the most widely recorded country songs of all time, and the royalties it brought in allowed Hartford great financial independence; Hartford would later say that the song bought his freedom.[1] As his popularity grew, he moved to the West Coast, where he became a regular on the "Smothers Brothers Comedy Hour"; other television appearances followed, as did recording appearances with several major country artists. The success on "SmoBro" was enough that Hartford was offered the lead role in a TV detective series but he turned it down to move back to Nashville and concentrate on his music. He also was a regular on the Glen Campbell's and Johnny Cash's television shows.

In other trivia, Albert Brumley wrote "I'll Fly Away" (featured on the movie Oh Brother Where Art Thou for which Hartford performed several soundtrack tunes) and also wrote "Turn Your Radio On,' which Hartford recorded on his "Aereo-plain" album.

This next video is JH and Glen Campbell on the Smothers Brothers show singing "Gentle On My Mind." Someone dressed JH in a turtleneck and told him to emote for the TV camera, which turned out awkward, but they sound good.

John Hartford sings "Gentle on My Mind" solo.

Elvis sings "Gentle on My Mind."