EXCLUSIVE: Rachel Brosnahan, most recently known for her Golden Globe and Emmy winning performance on Amazon’s The Marvelous Mrs. Maisel series, is set to co-star opposite Benedict Cumberbatch in Cold War drama, Ironbark. On Chesil Beach helmer Dominic Cooke is on board to direct the feature from a screenplay by The Hitman’s Bodyguard scribe Tom O’Connor.

The pic is based on the true story of Greville Wynne (Cumberbatch), a British businessman who helped the CIA penetrate the Soviet nuclear program during the Cold War. Wynne and his Russian source, Oleg Penkovsky, provided the crucial intelligence that ended the Cuban Missile Crisis.

Brosnahan, who was last seen on the big screen in Patriots Day with Mark Wahlberg, will play Emily Donovan, the brilliant, determined CIA agent who runs Wynne and Penkovsky’s espionage operation.

Ironbark is being produced by Ben Pugh and Rory Aitken of 42 alongside SunnyMarch’s Adam Ackland, and FilmNation Entertainment. Cumberbatch, Cooke, and O’Connor will serve as executive producers with 42’s Josh Varney and Leah Clarke of SunnyMarch.

FilmNation is fully financing the project and will handle international sales, while UTA Independent Film Group reps the US side.

Brosnahan made waves as Midge Maisel when The Marvelous Mrs. Maisel debuted in 2017. The show, which just took home the Emmy for Outstanding Comedy series, was picked up for a third season before its second season has aired. No word on when Season 2 will drop but it’s expected to be sometime this year.

Other credits for Brosnahan include Netflix’s House Of Cards, which she received an Emmy nom for her performance, the WGN series Manhattan, The Finest Hours, and Beautiful Creatures.

She’s repped by Brillstein Entertainment Partners, CAA, and Schreck Rose Dapello & Adams