John Clifford Farrar (born 8 November 1945) is an Australian music producer, songwriter, arranger, singer, and guitarist. As a musician, Farrar is a former member of several rock and roll groups including The Mustangs (1963–64), The Strangers (1964–70), Marvin, Welch & Farrar (1970–73), and The Shadows (1973–76); in 1980 he released a solo eponymous album.

The Shadows were an English instrumental rock group. They were Cliff Richard's backing band from 1958 to 1968 and on numerous reunion tours. The Shadows have had 69 UK chart singles from the 1950s to the 2000s, 35 credited to The Shadows and 34 to Cliff Richard and The Shadows.

As a songwriter and producer, Farrar worked with Olivia Newton-John from 1971 through 1989. He wrote her number-one hit singles: "Have You Never Been Mellow" (1975), "You're the One That I Want" (1978 duet with John Travolta), "Hopelessly Devoted to You" (1978), and "Magic" (1980).

"Hopelessly Devoted to You" is a song recorded by English-born Australian singer Olivia Newton-John for the musical "Grease" (1978). The song was released in Australia in August 1978 and peaked at number 2. It reached number three on the US 'Billboard' Hot 100 and number 2 in the UK charts.

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