She died at home in Sewickley, PA, where she had grown up and recently re-settled. Ms. Clarke, whose full named was Katherine Ann Clarke, was 52. Her friends called her "Kate."
Ms. Clarke studied at Mt. Holyoke College and Yale School of Drama, where she earned her MFA. In addition to film, TV and stage work, she taught acting at P.S. 58 in New York City in 1998-99 as part of an initiative by the Broadway Theater Institute. She taught drama at the University of Pittsburgh and taught young people in the Studio G program at Pittsburgh's Rauh Conservatory.
Her Broadway credits in the 1980s and '90s also included playing the alternate title role in Teaneck Tanzi: The Venus Flytrap. In Titanic, she took over the role of Charlotte Cardoza.
Her-Broadway credits include Othello (1979), No End of Blame (1981), Summer (1983), Quartermaine's Terms (1984), Thin Ice (1984), Total Eclipse (1984), Three Birds Alighting On A Field (1994) and Unexpected Tenderness (1994). Regionally, she appeared in Tales From The Vienna Woods (New Haven, 1978), The Winter's Tale (Washington, DC 1979), Bal (Chicago, 1980), Plenty (The Goodman Theatre, Chicago, 1981), Summer Vacation Madness (Minneapolis, 1982), Not Quite Jerusalem (New Haven, 1984), As You Like It (San Diego, 1984), Our Country's Good (U.S. Premiere, Los Angeles, 1989), The Queen And The Rebels (Baltimore, 1991), Mrs. Warren's Profession (New Haven, 1996), Indiscretions (Dallas, 1997), The Glass Menagerie (Portland, ME, 1997), Griller (Baltimore, 1999), Who's Afraid of Virginia Woolf (Geva Theatre, Rochester, 2000), Charlotte: Life? or Theater? (Philadelphia, 2001), The Gigli Concert (Pittsburgh, 2002), Aristocrats (Pittsburgh, 2002).
Her film appearances include the principal title role of Valerian in the fantasy picture, "Dragonslayer" (1981). According to the Pittsburgh Post-Gazette, Ms. Clarke made her acting debut at the age of 16, playing Marian the Librarian in The Music Man at Sewickley's Edgeworth Club.
She is survived by her parents, Charles and Cecelia, and four sisters: Victoria Clarke, Anne Ronce, Cecelia Clarke and Greensburg, and Constance Clarke.
According to the Post-Gazette, a memorial service and reception will be held from 5 to 8 PM Sept. 30 at the Edgeworth Club. The day is to include a dramatic performance by some of her friends.
Contributions for a memorial fund in her name may be sent to Pittsburgh Musical Theater, 327 S. Main St., Pittsburgh, PA 15220.