On 27 September 1975, John Denver reached number one on the US pop chart with “I’m Sorry”, a song written for his first wife, Ann Martell. The heartfelt breakup track reflected both his remorse and self-pity, while marking the height of Denver’s broad popularity across folk, country, soft rock and adult contemporary music.

The song also topped the adult contemporary and country charts, giving Denver his second country number one of 1975 after “Thank God I’m a Country Boy”. Denver and Martell, who married in 1967 and adopted two children, divorced in 1982 after the pressures of his fame strained their relationship; “I’m Sorry” later became his final pop chart-topper.