The Beatles recorded much of the Revolver album in Studio 3 (source: 'The complete Beatles recording sessions,' by Mark Lewison, page 82). This is the first recording session for "I'm Only Sleeping", E.M.I. Studio Three, 27th April 1966, 11.30 pm to 3 am of the 28th April. They are rehearsing what would be the actual backing track of the released take. Lennon on acoustic guitar, McCartney on bass guitar, Ringo on drums. Studio Three Steinway Model B piano in the foreground (source: commenter henry_the_horse).