There was no recording session scheduled for 18 April 1966, so John Lennon and George Harrison went to the Marquee Club in London, where they saw The Lovin' Spoonful perform.
Between 1964 and 1988 the Marquee Club was situated at 90 Wardour Street in Soho, London. On this night Harrison met Eric Clapton; the pair would become close friends in subsequent years. They had met once before, during Another Beatles Christmas Show at Hammersmith Odeon in 1964-65.
Afterwards Lennon and Harrison visited a London nightclub in the company of Brian Jones, Spencer Davis, Stevie Winwood and Tom McGuinness.
The Spoonful's John Sebastian was wearing Lennon-style granny glasses a full year before John himself! He even looked somewhat like the circa-'68 version of john. Check the cover of 1965's "Do You Believe In Magic" LP.
The Spoonful's early song "Good Time Music" contained a lyrical nod to the British Invasion, crediting "those boys from around the Merseyside" with helping to get that good old rock 'n roll back on American radio.