Paul Ritter (Electric Dreams, No Offence), Jessie Buckley (Taboo, Country Music), Adrian Rawlins (Darkest Hour, War and Peace) and Con O’Neill (Happy Valley, Telstar) have joined HBO’s miniseries Chernobyl, a co-production between HBO and Sky. They join previously announced Jared Harris, Stellan Skarsgård and Emily Watson.

Production on the miniseries began last month in Lithuania. Chernobyl will debut on HBO in the U.S. and on Sky Atlantic in their territories as well as on their streaming service NOW TV.

Written by Craig Mazin, the five-part miniseries dramatizes the true story of one of the worst man-made catastrophes in history — the April 26, 1986 explosion at the Chernobyl nuclear power plant in then- Ukrainian Soviet Socialist Republic — and tells of the brave men and women who sacrificed to save Europe from unimaginable disaster.

Also joining the large-scale production are Sam Troughton (The Ritual, The Hollow Crown), Adam Nagaitis (The Terror, To Walk Invisible), Ralph Ineson (Harry Potter and the Half-Blood Prince, Absentia), Mark Lewis Jones (Apostle, Star Wars Episode VIII), Fares Fares (Rogue One: A Star Wars Story, HBO’s Westworld) and David Densik (McMafia, Top of the Lake: China Girl).

Cast also includes Robert Emms, Jay Simpson, Gerard Kearns, Michael Socha, Jamie Sives, Kieran O’Brien, Karl Davies, Billy Postlethwaite, Alex Ferns and James Cosmo.

Cherynobyl is produced by Sister Pictures and the Mighty Mint as an HBO/Sky Television co-production. Carolyn Strauss executive produces with Jane Featherstone and Craig Mazin. Co-executive producing are Chris Fry and Johan Renck, who also directs. Sanne Wohlenberg produces.