Bonnie Brown, one of three siblings whose smooth harmonies as The Browns influenced generations of singers from the Beatles to Lady Antebellum, has died.
Her publicist, Kirt Webster, said Brown, 77, a former girlfriend of Elvis Presley, died in Little Rock, Arkansas, of complications from lung cancer.
With older siblings Jim Ed Brown and Maxine Brown, the three helped define the Nashville sound of the 1950s and 60s.
They were inducted into the Country Music Hall of Fame and Museum in 2015 after Jim Ed's death earlier that year.
The Browns, from Sparkman, Arkansas, began singing at school and church functions. In 1952 Maxine entered Jim Ed in a talent contest but he lost first place to a harmonica player, according to the Hall of Fame's website. But the radio station that ran the competition was impressed anyway and made him a regular.
Maxine soon joined him on stage and in TV appearances and the duo began recording hits. They were joined by their little sister, 18-year-old Bonnie, in 1955 and the trio's version of Here Today And Gone Tomorrow made it into Billboard's country Top 10.
The Browns were signed by RCA Records in 1956 and by the next year had more hits with I Take The Chance and I Heard The Bluebirds Sing, along with others.
The Browns crossed over into pop, folk and rhythm and blues, including the No 1 hit The Three Bells, previously a success for the French cabaret singer Edith Piaf.
The group disbanded in 1968 as Jim Ed and Maxine pursued solo careers. All three reunited in the 1980s and again in 2006 for a PBS special, Country Pop Legends.
Kyle Young, the Hall of Fame's chief executive, said the siblings created the "smoothest and most elegant blend in country music".
Off-stage, Bonnie once broke up with a young Elvis Presley "because he was, she said, a lousy kisser", according to Mr Young.