.... http://www.youtube.com/watch?v=cpAY25Awafo&NR=1
not to the video intially cited by Andrei (the violin player in the nightclub scene is not Uncle Nat).
http://www.youtube.com/watch?v=4Z3RL1fr7TE
You can see Uncle Nat in the terrific video of "I'm More Than Satisfied" by the Capitolians. He plays "single hair" violin!
http://www.dailymotion.com/video/x1gbm2_i-m-more-than-satisfied-the-capitol_music
Albert