Johnny Bush, the Texas-based singer-songwriter best known for writing the Willie Nelson classic "Whiskey River," has died. Multiple media outlets report that Bush died on Friday (Oct. 16) at the age of 85.

Bush's manager confirmed the singer-songwriter's death to Rolling Stone. According to the Houston Chronicle, Bush died of pneumonia, but the circumstances and whereabouts of his death are unclear.

Born John Bush Shinn III in Houston in 1935, Bush later moved to San Antonia, where he was based for most of his life. The versatile musician played guitar, drums and fiddle, but his exceptional singing voice became his calling card, causing one music critic to nickname him "the Country Caruso."

Bush got one of his big breaks when his friend Nelson helped him land a job playing in Ray Price's band with him. He later played in Nelson's band, which led to him landing a recording deal and scoring regional and national hits in 1968 and 1969 with “The Sound of a Heartache," “Undo the Right” and “You Gave Me a Mountain," all of which were released on the Stop label.

He signed to RCA in 1972 and released "Whiskey River" as his first single for the label. The song scored him his biggest hit, reaching No. 7 in Canada and No. 14 in the U.S., but vocal problems struck Bush soon after, causing him to lose much of his voice. RCA dropped Bush in 1974, and he struggled for years, sometimes unable to perform at all.

Bush scored his biggest success when Nelson recorded "Whiskey River," which Bush co-wrote with Paul Stroud, for his classic Shotgun Willie album in 1973. A subsequent live recording of the song from Nelson's 1978 album Willie and Family Live would reach No. 12 on Billboard's Hot Country Songs chart, and the song has gone on to become one of the most iconic hits of Nelson's career, serving as his show opener for decades.

Bush was ultimately diagnosed with a rare vocal condition called spasmodic dysphonia, and he regained much of his voice after working with a vocal coach and was able to resume his career, emerging in his later years as a mentor figure to younger Texas musicians and a regional success in his own right once again. He recorded and toured regularly up until nearly the end of his life, remaining friends with Nelson and often playing at his annual Fourth of July Picnics. According to Austin 360, he most recently performed at Riley’s Tavern in New Braunfels, Texas, on Sept. 25, and had a show scheduled in Fort Worth in November.

“Texas Country Music Hall of Famer, Country Music legend, nicknamed the Country Caruso, a friend to everyone in the music business, a friend to all of his fans, Johnny Bush passed away this afternoon surrounded by his family and some of his closest friends," a post to Bush's Facebook page stated Friday. "Please keep the Bush family in your heart and prayers. A jewel of a man we have lost.”

Funeral plans for Johnny Bush have not been announced.

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