EXCLUSIVE: Elisabeth Moss is set to join Robert Redford and Cate Blanchett in Truth, the film about the scandal that erupted after Dan Rather reported on 60 Minutes II that George W. Bush had gotten preferential treatment that put him in the Texas Air National Guard to avoid the Vietnam War draft. The ensuing scandal during Bush’s re-election campaign left Rather’s reputation in tatters and his key producer Mary Mapes fired.

James Vanderbilt, the A-list screenwriter behind the first two installments of The Amazing Spider-Man, is making his directorial debut on the pic, which is based on Mapes’ 2005 memoir Truth And Duty: The Press, The President, And The Privilege Of Power. Redford is aboard to play Rather and Blanchett will play Mapes. Moss will play CBS veteran Lucy Scott, now a journalism professor in Dallas, who is brought on board by Mapes as her new associate producer to “run point” on the story controversy.

Moss has been busy. The Mad Men alum has already wrapped that series — for which she has five Emmy noms — with the final seven episodes returning in April, and she was just tapped to star in the Broadway revival of The Heidi Chronicles which will begin early next year. On the film side she is shooting Alex Ross Perry’s Queen Of Earth and also just wrapped work on Reed Morano’s Meadowland and Ben Wheatley’s High Rise. She is repped by WME and Ribisi Entertainment Group.