Co-starring Ellen Burstyn, Frances Fisher, Michael Gross, Philip Baker Hall, Cloris Leachman, Mary McDonnell, Chloe Sevigny, Bill Smitrovich and Frank Whaley, the HBO-financed movie marks Nagy's film directorial debut.
The film's producers said the movie started shooting last month in Los Angeles.
"Mrs. Harris" is the real-life story of Jean Harris (played by Bening), who killed her lover, Dr. Herman "Hy" Tarnower (played by Kingsley), a respected cardiologist and author of the best-selling "The Complete Scarsdale Medical Diet," which caused a media sensation in the 1980s.
Wisconsin business offering 'therapeutic cuddling' forced to close
Reindeer recovered after escaping from Santa during lighting ceremony