I have seen B.B. many times - every show was fabulous. I remember one show however, many years ago when his emcee said and "And now ladies and gentleman (Beeeem - that unmistakable vibrato and tone from off-stage) the King of the Blue (Beeeem) Mr. B. (Beeeem) B. (Beeeem) King! and he walked out playing "Everyday I have the Blues" on Lucille.
Amazing how you could tell who was playing just from the wonderful and unique tone and vibrato of the Master!