The Beatles - A Day in The Life: June 17, 1965 (Thursday)
'Yesterday' was fully completed this day. The string quartet included: Tony Gilbert (first violin), Sidney Sax (second violin), Francisco Gabarro (cello) and Kenneth Essex (viola). Complete now in its stunning simplicity, the song was mixed into mono.
The rejection of 'If You've Got Trouble', recorded on February 18, meant that Ringo had still to record a lead vocal for the now almost completed Help! album. Being a country western fan, he plumped for a cover of 'Act Naturally' by Buck Owens and the Beatles recorded it in 13 rhythm track takes. George played acoustic guitar, Paul provided harmony and Ringo overdubbed his vocal.
The Beatles recorded a new Lennon-McCartney song called 'Wait'. It was left unissued until in urgent need of one more sons, the Beatles pulled the tape from the library shelf, polished it up and included it on Rubber Soul.
Source: The Complete Beatles Chronicle by Mark Lewisohn