Litvinenko made its ITV debut on Monday night and viewers who tuned in to watch the drama are saying the same thing about it.
The four-part series, which stars David Tennant in the titular role, tells the true story of an ex-Russian spy, Alexander Litvinenko, whose death from Polonium-210 poisoning in November 2006 activated one of the most dangerous investigations in the history of the Metropolitan Police.
Taking to Twitter, viewers were quick to praise the drama, with one person writing: "Powerful, moving, gripping, well written," while another added: "#Litvinenko first episode watched tonight and wow. Such a powerful show. So brave of everyone involved to make this. You can tell this is going to be amazing. Very sad the story behind it."
Many viewers also praised David Tenannt's compelling performance, with one person tweeting: "David Tennant in #Litvinenko was superb. Just awesome," while another added: "Started watching #Litvinenko earlier. Gripping. What a brave man. And #DavidTennant is sensational."
A third person commented: "After all these years, I shouldn't be surprised at yet another incredible performance (& transformation) from David Tennant, but he's done it again," while another agreed, adding: "Wow #Litvinenko has to be up there with David Tennant best work."
READ: ITV's Litvinenko: the chilling true story behind David Tennant's new drama
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Fans of ITV drama, The Bay, couldn't help but notice a cast 'reunion' in episode one, as both actors Daniel Ryan and Barry Sloane, who star in the popular detective series, appear in the new drama.
One person tweeted: "Any fans of #TheBay will enjoy #Litvinenko with both @_DanielRya and @BarrySloane reuniting in it," while another wrote: "I think it's brilliant. I love the cast. Particularly the ones from #TheBay. Such a tense sad story. #DavidTennant was fabulous #Litvinenko."
What is Litvinenko about?
The series tells the story of the "the determined New Scotland Yard officers" who worked to prove who was responsible for the death of former Russian intelligence officer Alexander Litvinenko.
In November 2006, two police officers were called to University College Hospital in London to interview a patient who claimed to have been poisoned on the direct orders of Vladimir Putin.
The synopsis continues: "During the police interviews, Alexander provided meticulous details from his hospital bedside about the events leading up to his illness, which he knew would prove fatal. His information would ultimately help detectives track down two Russians who had poisoned Litvinenko with Polonium-210, a highly toxic radioactive substance."
The drama also follows the story of Alexander's widow, Marina, who "fought tirelessly to persuade the British Government to publicly name her husband's killers and acknowledge the role of the Russian State in his murder".