The fifth Beatle is an informal title that various commentators in the press and entertainment industry have applied to people who were at one point a member of the Beatles, or who had a strong association with the "Fab Four" (John Lennon, Paul McCartney, George Harrison, and Ringo Starr) during the group's existence. The "fifth Beatle" claims first appeared in the press immediately upon the band's sensational rise to global fame in 1963–64 as the most famous quartet in pop culture.
The term is not used to indicate the chronology of band members joining the group. Pete Best joined Lennon, McCartney, Stuart Sutcliffe and Harrison on the eve of their Hamburg sojourn, the five using the monikers, "The Silver Beetles" and "The Silver Beatles" (they experimented with "The Beat Brothers" and ultimately "The Beatles" while in Hamburg with Best).
Stuart Sutcliffe has been called the fifth Beatle. The original bassist of the five-member Beatles, he played with the band primarily during their days as a club act in Hamburg, Germany. When the band returned to Liverpool in 1961, Sutcliffe remained behind in Hamburg. He died of a brain haemorrhage shortly thereafter. Instead of replacing him with a new member, McCartney changed from rhythm guitar (with Lennon) to bass and the band continued as a four-piece.
Sutcliffe was an accomplished painter, but when compared to the other Beatles, his musical skills were described as "inadequate", and his involvement in the band was mainly a consequence of his friendship with Lennon. Sutcliffe's input was an important early influence on the development of the band's image; Sutcliffe was the first to wear what later became famous as the Beatles' moptop hairstyle, asking his girlfriend Astrid Kirchherr to cut his hair in emulation of the hairdo worn by friend Klaus Voormann.