Don Cheadle‘s a man of many talents. While the star of Sony Classics’ “The Guard” was waiting at WNYC for an interview to start on Leonard Lopate‘s show this week, he killed time by uncovering a piano in the green room and spontaneously tickling the ivories. Station staffers, stunned by Cheadle’s impromptu performance, all emerged from their offices to enjoy the concert. Cheadle played classical selections from the soundtrack of the 1981 film “Diva.” In “The Guard” [See review] he plays an FBI agent who travels to Ireland to bust up a drug-smuggling ring.