Rehearsals began at Twickenham Film Studios in January 1969 as part of a planned documentary showing the Beatles' return to live performance. Paul McCartney conceived the project as an attempt to reinvigorate the band by returning to simpler rock and roll configurations. The filmed rehearsals were marked by ill feeling, leading to George Harrison's temporary departure from the group. As a condition of his return, the members reconvened at their own Apple Studio with guest keyboardist Billy Preston. The project then yielded a single public concert held impromptu on the studio's rooftop on 30 January, from which three of the album's tracks were drawn.