Naomi Watts Babe Paley Actor Tom Hollander Truman Capote Actor Diane Lane Slim Keith Actor Chloë Sevigny C.Z. Guest Actor Calista Flockhart Lee Radziwill Actor Demi Moore Ann Woodward Actor Molly Ringwald Joanne Carson Actor Treat Williams Bill Paley Actor Joe Mantello Jack Dunphy Actor Russell Tovey John O'Shea Actor Ryan Murphy Executive Producer, Writer Alexis Martin Woodall Executive Producer Jon Robin Baitz Executive Producer, Writer Gus Van Sant Executive Producer, Director