This is interesting: According to music blog I Am Fuel, You Are Friends, between the years of 1973 and 1975 (a period of time known as The Lost Weekend), John Lennon wandered around working with all sorts of various musicians, like David Bowie, Elton John and Mick Jagger. According to this blogger:
The track he laid down with Mick Jagger was, for a long time, just mythical. In 2003, a London record store owner put an unlabeled record up for auction which he claimed had come originally from Ronnie Wood (guitarist for the Stones) and contained a collaboration cover of Jagger singing the old Willie Dixon blues song, "Too Many Cooks" with Lennon on guitar. That unlabeled acetate (made directly from a master tape, and found in a stack of records) sold for £1,400, and Mick admitted that he had forgotten it existed for a number of years.
This October 2, Jagger is releasing a compilation album which will feature three previously unreleased tunes — including the "Too Many Cooks (Spoil the Soup)" on which Lennon may be playing guitar.
The song is a brassy, groovalicious tune with Jagger's big ol' voice letting loose in a soulful way. If this song doesn't get you swinging your hips, I don't know what will, so to check it out,
By way of I Am Fuel, You Are Friends