Peter Sarsgaard just joined the cast as Robert Kennedy. Gerwig will play one of the former First Lady’s aides.
Pablo Larrain is directing the movie, while Darren Aronofsky is producing along with his partner Scott Franklin at Protozoa Pictures and Juan de Dios Larrain of Chile’s Fabula.
The film follows the first four days in Jackie Kennedy’s life after her husband President John. F. Kennedy’s assassination.
International rights for the film were sold at the recent Cannes Film Festival while CAA is still repping domestic rights as it looks for a distributor. Production on the project is expected to begin at the end of 2015.
Gerwig was most recently seen in Noah Baumbach’s “Mistress America.” She is repped by UTA and Management 360.