The Marvelettes, an all-girl group achieved popularity in the early to mid-1960s.
In early 1963, the group was shortened to a quartet when Juanita Cowart opted to leave the band citing a mental breakdown—caused by stress from performing on the road and a mistake she made in describing the group’s background during an appearance on American Bandstand. Carrying on as a quartet, the group issued one of Holland–Dozier–Holland’s early compositions, “Locking Up My Heart”, which peaked at #44. It was one of the first singles to feature Horton and Young in co-leads. The success of “Locking” was probably tested due to strong airplay by the song’s B-side, the Young-led ballad “
“, which also received a pop charting, peaking at #78.