Claim: Oh Yeon-seo is a previous member of a band.

A girl group is a music act featuring several female singers who generally harmonize together . The term `` girl group '' is also used in a narrower sense in the United States to denote the wave of American female pop music singing groups , many of whom were influenced by doo-wop , and which flourished in the late 1950s and early 1960s between the decline of early rock and roll and start of the British Invasion .   All-female bands , in which members also play instruments , are usually considered a separate phenomenon . These groups are sometimes called `` girl bands '' to differentiate , although this terminology is not universally followed .   With the advent of the music industry and radio broadcasting , a number of girl groups emerged , such as the Andrews Sisters . The late 1950s saw the emergence of all-female singing groups as a major force , with 750 distinct girl groups releasing songs that reached US and UK music charts from 1960 to 1966 . The Supremes alone held 12 number-one singles on the Billboard Hot 100 during the height of the wave and throughout most of the British Invasion rivaled the Beatles in popularity . In later eras , the girl group template would be applied to disco , contemporary R&B , and country-based formats , as well as pop . A more globalized music industry saw the extreme popularity of dance-oriented pop music led by major record labels . This emergence , led by the US , UK , South Korea , and Japan , produced extremely popular acts , with eight groups debuting after 1990 having sold more than 15 million physical copies of their albums . Also , since the late 2000s , South Korea has had a significant impact , with 8 of the top 10 girl groups by digital sales in the world originating there .