Jackie Kennedy is of course the First Lady, wife of JFk who has to due with his assassination in 1963. The film will focus on her for the four days between the assassination in Dallas and the burial period. It means, Weisz would have to show "both her most vulnerable and her most graceful" performance ever "as she bears up under the pressure of horrific circumstances and unprecedented public attention."
There were rumours in the past linking the project to a Spielberg's outing for HBO TV movie but now it seems to be entirely untrue. So now, it's a chance for Aronofsky to continue his fine work in The Wrestler.
SOURCE: CinemaBlend, Entertainment Weekly