Dunaway, who owns the screen rights to the property, did the play on tour last year and had hoped to do it on Broadway, but the drama closed in the middle of her tour after a substantial run.
Onassis appeared only in Callas' memory in McNally's play.
The Oscar winner hopes that Audra McDonald (as La Callas' most defiant student) and McNally will reprise the Tony-winning work for the movie edition. She told Playbill On-Line that she also expects Leonard Folgia, who directed the play and the current Wait Until Dark, will make his movie-directing debut with the project.
The only question remaining is: When? "We need to shoot it at the end of the summer," she says, "but I don't think we'll make it this year."