Muddy was quite aware of how his bread was getting all that extra butter, excellent move on his part. With Ron being with both Keith and Mick this had to have been between 74 - 82.
Members of the greatest Rock N' Roll band sitting in with one of the originators, who would have ever thought? (Tee, Hee!).
At 1:40 one can see Keith in the background, he is seated, he pulls out his knife , he opens a bottle(whiskey, bourbon??) and then he takes a swing at it. That's Keith Richards for you! Rock and Roll, Mops