Classes are usually tough, but a master class goes without saying. The one-on-one attention is sure to set off butterflies in the ol stomach, but the thought of having opera legend Maria Calls as your instructor ... now thats enough to get folks shuddering in fear. That said, Carolina Actors Studio Theatre is stretching to hit the high notes in performances of Terrence McNallys Master Class, which kicked off yesterday. Callas, known for her rather cruel lessons in the art of singing and whose spotlight both onstage and in the public eye was spawned by her love affair with a rich Greek ship owner named Aristotle Onassis has some stories to tell. And deep down, you know youre curious. Continues through Oct. 3. Tickets are $20-$25; $40 for dinner at Cafe Central and show; $37 for dinner at Dilworth Neighborhood Grille and show. Performance dates and times are: Sept. 12, 8 p.m.; Sept. 17-19, 8 p.m.; Sept. 20, 2:30 p.m.; Sept. 24-26, 8 p.m.; Sept. 27, 2:30 p.m.; Oct. 1-3, 8 p.m. Carolina Actors Studio Theatre is located at 1118 Clement Ave. For more information, call 704-455-8542.