'The Catcher Was A Spy' adds Sienna Miller to cast

Sienna Miller is one of the latest names to be added to "The Catcher Was A Spy" reports Deadline.

Giancarlo Giannini has also been confirmed for the Ben Lewin-directed movie, which also stars Paul Rudd, Guy Pearce, Paul Giamatti and Jeff Daniels.

Adapted from Nicholas Dawidoff's bestselling book the film tells the true story of Moe Berg, a major league ballplayer who was an important spy against the Nazis in WWII.

An Ivy League graduate with a law degree who spoke nine languages, Berg was an average catcher but a better spy, with his efforts working for the OSS helping America to win the race against Germany to build the atomic bomb.

Miller is set to play Estella Huni, Berg's love interest, with Giannini confirmed for the role of Italian physicist Professor Eduardo Amaldi.