The 36-year-old actress said that she came to know about the project, which is based on politician's time as a lawyer in the 1970s, on the internet, reported Digital Spy.
Asked about the Clinton movie rumours, Chastain said "No, that's actually not true. I found out about the project online, but, yeah, there's a lot of stuff out there."
Chastain, who was speaking at the Sound of Change concert here, admired her "Tree of Life" co-star Brad Pitt for "see(ing) everyone as equals" and supporting the women's empowerment gig.
Scarlett Johansson, Reese Witherspoon and Amanda Seyfried are among the other actresses in the race to play Clinton in "Rodham".