Brian, Mike Love, Al Jardine, Bruce Johnston and David Marks (the original stand in for Al Jardine for a year or so in the very early days)
Apparently it's a 50 song set list, and they have 'dubbed in' Carl singing God Only Knows from beyond the grave.
I've plucked this one from Google, but pretty sure I heard similar on the Anthology documentary.
Lucy In The Sky With Diamonds | The Beatles Bible
Either way it seems to have unintenionally written about LSD originally, but with obvious connotations on the face of it.
Might bookmark that site...