Movie producer Jerry Weintraub, who was instrumental in the career of John Denver, has passed away at the age of 77. The legendary entertainment mogul died on Monday (July 6) in California after suffering a heart attack.

According to The Guardian, Weintraub came from humble beginnings in Brooklyn and worked his way from the mail room of the William Morris Agency to become one of the top concert promoters in the music business, working with stars as diverse as Frank Sinatra, Elvis Presley, the Moody Blues and Denver.

Weintraub helped launch Denver's solo career after the singer-songwriter left the Chad Mitchell Trio and set out on his own, moving from folk to country and pop. Beginning in 1970, Weintraub steered Denver's rise from obscurity to becoming the best-selling musical artist in America, with hits including "Take Me Home, Country Roads," "Annie's Song," "Rocky Mountain High" and "Sunshine on My Shoulders," among others. He parlayed Denver's fame into a movie deal for Oh God!, in which Denver starred opposite George Burns as an ordinary man who is chosen to spread God's message on Earth.

The movie was a hit in 1977, launching Weintraub into a spectacularly successful second career as a motion picture producer, with an enormous list of credits that included The Karate Kid, Ocean's Eleven, Pure Country, Nancy Drew and more. That success drove a wedge between him and Denver, who felt his manager was neglecting him for his newfound producing career. They had a professional and personal falling out that Weintraub said was one of his big regrets, since they never reconciled before Denver's death in 1997.

"I considered him a great friend," Weintraub wrote in his autobiography, When I Stop Talking, You'll Know I'm Dead. "He was in my will as one of the executors of my estate, taking care of my kids should anything happen to me. We were that close."

Weintraub's most recent success was producing the Liberace biopic Behind the Candelabra for HBO, which won 11 Emmys. He is survived by his wife, Jane, from whom he was separated but not divorced; four children, Michael, Julie, Jamie, and Jod;, his longtime companion, Susan Ekins; a brother, Melvyn, and five grandchildren.

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