Nicholas King (left) plays young Nick Burns in A Thousand Clowns, which opened at the Longacre July 11. With King is his understudy Ricky Ashely. Also in the cast are Mark Blum (left) who plays Leo with Robert LuPone (A Chorus Line, True West) as Arnold Burns. Selleck stars as the iconoclastic, slovenly and free spirited Murray Burns in A Thousand Clowns. An unemployed TV writer, Burns struggles to raise his nephew Nick (Nicolas King) just the way he wants, without interference from his friends, neighbors and the pretty social worker (Sandra Markowitz) assigned to his case. A Thousand Clowns runs through Oct. 14.