Laura Linney is in talks to join the film about WikiLeaks' founder Julian Assange, according to reports.
Sherlock star Benedict Cumberbatch has already been tipped to take the lead role in the movie directed by Bill Condon.
The Wrap said James McAvoy is also in talks for the project to play Assange's former right-hand man Daniel Domscheit-Berg.
It's not yet known which role Hyde Park On Hudson star Laura would play.
Domscheit-Berg wrote one of the books - Inside WikiLeaks: My Time With Julian Assange At The World's Most Dangerous Website - that the script for the film is based on.
The film is also based on WikiLeaks: Inside Julian Assange's War On Secrecy by David Leigh and Luke Harding.
Former West Wing writer Josh Singer penned the script.