''For most people, acting is faking, but I don't think it is for Julianne,'' says playwright David Hare of Julianne Moore, star of his new play, The Vertical Hour. On Nov. 30, the 45-year-old actress makes her long-overdue Broadway debut portraying an Iraq war correspondent-turned-Yale professor. ''I never write with anyone in mind,'' says Hare, but he and the play's director, Sam Mendes, ''both immediately said that Julianne Moore was the person for it.'' Why Moore? He pointed to her performance in 1995's Safe (''No one plays that state of benumbed victimhood better'') as a precursor to her demanding Vertical Hour role. Hare, 59, has worked with the flame-haired actress before: He adapted The Hours, the 2002 film that earned Oscar nominations for both of them. ''In Europe, alongside Meryl Streep, she's regarded as the greatest American actress. She's not going to offer a forced or false thought or emotion. If the text doesn't warrant the feeling, she won't give you the feeling.''