The Everly Brothers (Don Everly, born Isaac Donald Everly February 1, 1937, Brownie, Muhlenberg County, Kentucky, Phil Everly, born Phillip Everly, January 19, 1939, Chicago, Illinois) are brothers and top-selling country-influenced rock and roll performers, known for steel-string guitar playing and close harmony singing. The Everlys are the most successful U.S. rock and roll duo on the Hot 100. Their greatest period came between 1957 and 1964.
The brothers are both guitarists and use a simple vocal harmony mostly based on parallel thirds. With this, each line can often stand on its own as a melody line. This is in contrast to classic harmony lines which, while working well alongside the melody, sound strange by themselves. One example of their close-harmony is "Devoted to You".
The duo's harmony singing had a strong influence on rock and roll groups of the 1960s. The Beatles, The Beach Boys, and Simon and Garfunkel developed their early singing style by performing Everly covers. The Beatles based the vocal arrangement of "Please Please Me" upon "Cathy's Clown."