Different genres, different generations, both virtuosos

Even by the hyper-individualistic standards of the piano world, jazzman Herbie Hancock and classicist Lang Lang are as unorthodox as duo-piano pairings get. Put them together with the almost-never-heard Ralph Vaughan Williams Concerto for Two Pianos and Orchestra, and Thursday's final program of the Philadelphia Orchestra's Mann Center season also has the greatest curiosity factor.

What makes the most sense is the pair's collaboration on Gershwin's Rhapsody in Blue. They played an abbreviated version on the 2008 Grammy Awards telecast and are now touring Europe and the United States, using it as a jumping-off point for improvisation.

But as effortless as these concerts may look, Hancock readily admits, "We're kind of pushing each other over the edge." He's getting used to following a classical conductor, while Lang Lang is acclimatizing to jazz fans who applaud solos in the middle of a piece.