Director Jonathan Demme told the Los Angeles Times that Keith, who had been staying at Young’s California ranch, died of a heart attack.

Demme _ who directed Young’s concert films _ said Keith had been staying at the ranch working on new projects with his longtime collaborator.

Demme called Keith “an elegant, beautiful dude, and obviously a genius.”

Most recently, Keith had been touring with Young’s wife, Pegi, in support of her second solo album, “Foul Deeds,” for a handful of performances.

He also had played earlier this year with Neil Young on his first totally acoustic tour in several years.

Keith met Young in 1971 in Nashville, where the rocker was working on what would become his commercial breakthrough album, “Harvest.”

Their association ran through such Young albums as “Tonight’s the Night,” “Comes a Time,” “Harvest Moon,” “Greendale” and “Chrome Dreams II.”

He also was featured as an actor, in the role of Grandpa Green, in Young’s film of the stage production of the “Greendale” concept album.

Keith, who was born in 1937, played live or in the studio with artists including Emmylou Harris, Linda Ronstadt, Willie Nelson, Waylon Jennings, Ringo Starr and Crosby, Stills and Nash.

The Los Angeles also said on its website that Keith also produced singer-songwriter Jewel’s 1995 debut album, “Pieces of You.”

Among his own recordings, Keith released “Seven Gates” in 1994, a holiday collection in which he accompanied such high-profile friends as Johnny Cash, songwriter J.J. Cale and Neil and Pegi Young.