Erin Morley and Elīna Garanča sing Sophie and Octavian’s Act III duet in Der Rosenkavalier. The Met’s first new production since 1969 of Strauss’s rich, romantic masterpiece stars Renée Fleming in one of her signature roles as the Marschallin, opposite Elīna Garanča as Octavian, the impulsive young title character, on Great Performances at the Met Sunday, September 3 at 12PM on PBS (check local listings).