Musicians are not meant to be confined to one facet of their craft. Renée Fleming, one of the foremost voices in opera today, is not shy about her love for jazz and the mastery that goes into the highly improvisational form. In discovering Patricia Barber, she found a jazz songwriter and singer who, as it turns out, has an incredibly high regard for the operatic style. In their one night only concert at The Kennedy Center’s Terrace Theater, they proved that the two genres can go together magically.