I'm not sure if these have been posted before, but I don't have time to go through all 290+ pages of this thread... Michael Nesmith with Ringo Starr Jimi Hendrix, Michael Nesmith, and Peter Tork Michael Nesmith and Jack Nicholson
The Monkees (Micky Dolenz, Mike Nesmith, and Davy Jones) on the Glen Campbell Good Time Hour, 1969. Glen Campbell played as a session guitarist on multiple Monkees albums.
There's several pictures of the event. Google "Bowie Peter Sellers". Keith Moon and Joe Cocker were there too.