Guitarist Kirk Hammett (left) and his band Metallica will join classical pianist lang Lang on stage at the Grammy wards telecast Sunday night. Getty Images/Courtesy of the artist hide caption

itoggle caption Getty Images/Courtesy of the artist

Pianist Lang Lang sits down with his own revered mentor Gary Graffman, to discuss what makes great teachers — and bad ones. Courtesy of the artist hide caption

itoggle caption Courtesy of the artist