Stellan Skarsgård (Avengers: Age of Ultron) and Emily Watson (The Dresser) are set to star opposite Jared Harris in HBO’s miniseries Chernobyl, a co-production between HBO and Sky.

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.

Skarsgård will play Boris Shcherbina, the Deputy Chairman of the Council of Ministers and head of the Bureau for Fuel and Energy of the USSR. A relatively minor figure in the Kremlin, he is assigned to lead the government commission on Chernobyl in the early hours following the accident, when the government was still unaware the reactor had exploded. As the ranking official in charge of the effort to confront an unprecedented disaster, Shcherbina finds himself trapped between the realities of the political system he serves… and the brutal human costs of battling an escalating nuclear nightmare.

Watson will portray Ulana Khomyuk, a Soviet nuclear physicist committed to solving the scientific mystery of what led to the disaster at Chernobyl, so that it can be prevented from ever happening again. Her efforts put her on a collision course with those who have buried a terrible secret, and she must risk her freedom… and her life… to see that the truth is told, and justice is done.

Harris plays Valery Legasov, the Soviet scientist chosen by the Kremlin to investigate the accident.

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.

“Nobody would see it as a privilege to spend five months in a dilapidated nuclear plant, unless it was to play in a script like this by Craig Mazin, work with a director like Johan Renck, collaborate with a producer like Jane Featherstone, jam with an actor like Jared Harris and finally be at the feet of Emily Watson whom I have been missing for some twenty years,” Skarsgård said.

Chernobyl reunites Skarsgård and Watson who starred together in 1996 Cannes Film Festival winner Breaking the Waves.

“This is a significant piece of work and I’m honoured to be part of it. I can’t wait to get started with this amazing group of people, and am especially excited to be working with Stellan again,” Watson said.

Chernobyl will begin filming in Lithuania in Spring 2018. It will air on HBO in the US, on Sky Atlantic and NOW TV in the UK and Ireland, and on Sky Atlantic in Italy, Germany and Austria.

Skarsgård recently co-starred in Janus Metz’s Borg McEnroe, which opened the 2017 Toronto Film Festival and is currently in production on holocaust drama The Painted Bird and Hans Petter Moland’s Out Stealing Horses. He next reprises his starring role in the Mamma Mia! sequel. On the TV side, Skarsgård guest-starred on Cinemax’s Quarry and starred as the title character in miniseries River. He’s repped by Curtis Brown and ICM Partners.

Oscar-nominated Watson was most recently seen in National Geographic Channel’s Emmy-nominated drama series Genius, she led the cast in the BBC1’s Apple Tree Yard and also co-starred in the BBC/Masterpiece Theatre miniseries Little Women. She’ll next be seen in a starring role in Richard Eyre’s BBC/Amazon production of King Lear, opposite Anthony Hopkins, Emma Thompson and Florence Pugh, and in The Happy Prince alongside Rupert Everett and Colin Firth. She’s repped by Independent in the UK and UTA in the U.S.