Bobby Rush, King of the Chitlin' Circuit Taiwo Gaynor EXCLUSIVE: Grammy-winning blues musician Bobby Rush, fresh off Oscar winner Sinners, is the subject of new documentary King of the Chitlin' Circuit. The 92-year-old blues vet performed the harmonica parts for the character of Delta Slim in Sinners and recently took part in the on-stage Oscar night performance for the movie. The doc, which is due to air on Mississippi Public Broadcasting in August, will chart Rush's seven-decades career and personal journey.