This is not to say that they did not let off steam by jamming on occasion. I have a bootleg of them going on at length after a take of She's A Woman in 1964. 12 Bar Original was a failed attempt at an instrumental album track from the Rubber Soul sessions. Following the months of concentrated work on Sgt. Pepper, they sometimes wasted entire evenings in the studio during the spring of 1967 playing long unstructured jams, much to the dismay of producer George Martin and other Abbey Road staff members.
During the Get Back sessions, the band and their guest Billy Preston frequently lapsed into idly playing many of their favorite oldies. But on January 24th, 1969, they did something completely uncharacteristic and launched into an attempt at an extended jam called Dig It led by John. This version featured a slide guitar, although it would be completely forgettable if not for John's comment, "That was Can You Dig It by Georgie Wood. And now we'd like to do 'ark the Angels Come," at the end.
Two days later, they had another go at it with John and George on their guitars, Ringo on drums, Paul on piano and Billy on electric piano. Linda Eastman's 6-year-old daughter Heather joins in vocally early on and George Martin handles a percussive shaker. Otherwise, the group rambles on tediously for twelve and a half minutes playing the same old riff with John ad libbing and Paul adding a half-hearted, out of tune complementary vocal. On film, George and Billy, sitting side by side, do seem to be genuinely enjoying themselves.
When assembling both Get Back albums, producer/engineer Glyn Johns used the final four minutes of the second version, then tacked on Lennon's comment from version one. This preceded Let It Be on his proposed May '69 line-up and The Long and Winding Road on his revised January '70 line-up. For the Let It Be album, producer Phil Spector wisely trimmed down this section to less than a minute, using what is truly the only clever wordplay from the entire number. He then used Lennon's comment to segue directly into Let It Be.
In 2003, the Let It Be...Naked album stuck the final half minute of version one, which includes John's now-famous comment at the end, onto the bonus disc Fly on the Wall.