Jared Harris
Valery Legasov

Stellan Skarsgård
Boris Shcherbina

Emily Watson
Ulana Khomyuk

Paul Ritter
Anatoly Dyatlov

Jessie Buckley
Lyudmilla Ignatenko

Adam Nagaitis
Vasily Ignatenko

Sam Troughton
Alexandr Akimov

Robert Emms
Leonid Toptunov

Con O'Neill
Viktor Bryukhanov

Adrian Rawlins
Nikolai Fomin

Alan Williams
KGB Chairman Charkov

David Dencik
Mikhail Gorbachev

Mark Lewis Jones
General Pikalov

Ralph Ineson
General Tarakanov

Barry Keoghan
Pavel

Alex Ferns
Glukhov

Fares Fares
Bacho

Michael McElhatton
Prosecutor Andrei Stepashin