David Tennant "craved" the approval of Alexander Litvinenko's family when he agreed to play him in a new TV show.
David Tennant stars in Litvinenko
The 51-year-old actor stars as the former Russian Federal Security Service (FSB) officer-turned-British intelligence advisor - who died in London in 2006 after being poisoned - in ITVX's new three-part series 'Litvinenko' and he was pleased he had the opportunity to meet his widow Marina before filming began.
He said: "It's a story that has repercussions every day that we live through, you're very aware of that.
"Once you meet Marina, you feel you're not only carrying the importance of this story as a fable for our times, as a signifier for things that the world needs to be alerted to, you're also carrying the story of a family and the story of a couple and that felt very precious and very delicate.
"It’s something that we were all acutely aware of the whole time… it means so much to us Marina and [Alexander’s son] Anatoly give us their blessing, That’s the one thing we've all craved, because this is a hugely important story for the world, [but] it's also the story of a family and that’s something that was with us every minute on set."
David vividly remembered the story unfolding at the time and was impressed with how writers tackled the subsequent investigation for the show.
He said: "I remember being appalled and bewildered and shocked and confused by the news story, like the rest of the world was.
"And then to read the way that George [Kay] had written the script and told the story was captivating and compelling."
The veteran actor found it particularly "intense" shooting scenes where Litvinenko carried out scenes from his hospital bed.
He said: "Jim [Field Smith, director] helped us by giving us space and allowing us to inhabit that moment, as much as you ever can," he said. "A film set by its very nature is an artificial construct, but you do all you can to try and get past that.
"When I was in the bed, I tended to stay in the bed, and the crew were very respectful about sort of being… not at a distance, very much connected to the action, but being very respectful of the sorts of processes everyone needed to go through, because it did feel very intimate."
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