Preston is one of several people referred to as the "Fifth Beatle". At one point during the "Get Back" sessions, John Lennon proposed the idea of having him join the band (to which Paul McCartney countered that it was difficult enough reaching agreements with four). Preston played organ and electric piano for the Beatles during several of the "Get Back" sessions; some of these sessions appeared in the film "Let It Be" and on its companion album. Preston also accompanied the band on electric piano for its rooftop concert, the group's final public appearance. In April 1969, their single "Get Back" was credited to "The Beatles with Billy Preston", the only time such a joint credit had been given on an official Beatles-sanctioned release (as distinct from an unsanctioned reissue of some Hamburg-era recordings on which they were the backing group for Tony Sheridan). The credit was bestowed by the Beatles to reflect the extent of Preston's presence on the track; his electric piano is prominent throughout and he plays an extended solo. Preston also worked, in a more limited role, on the "Abbey Road" album, contributing organ to the tracks "I Want You (She's So Heavy)" and "Something".