Game of Thrones actor Mark Gatiss talks about reuniting with Kit Harington for HBO's Gunpowder

HBO’s new 17th century-set drama Gunpowder caused a media storm in an antique teacup when it screened in the U.K. earlier this year thanks to the three-part show’s graphic scenes of violence, including one sequence in which a woman is executed by being literally crushed to death.

“It was a real thing called ‘pressing,'” says cast member Mark Gatiss (Game of Thrones, Sherlock) over the phone from Britain. “In fact, it’s in The Crucible. It’s where they pile weights on top of you to. They would literally put a door on top of you, and weigh it down, until your back broke. There was quite a lot of controversy over here about how graphic the torture was, but it’s what they did, and if it had been stinted on, there would have been just as many complaints, saying history was being whitewashed, I imagine. But it’s pretty brutal stuff. And, without pushing the contemporary parallels, it’s happening now. Things we used to congratulate ourselves upon consigning to history are just back in terms of medieval torture, and imprisonment, and general persecution. I think the show feels very much now as well as 1605.”

The miniseries details the story behind the so-called “Gunpowder Plot” in which a group of English Catholics led by Robert Catesby attempted to blow up the House of Lords in London. Gatiss plays Robert Cecil, 1st Earl of Salisbury, and a ruthless government minister in the service of the Protestant King James I. “It’s the early years of the reign of James I, who inherited the throne from Queen Elizabeth, and Robert was, essentially the Prime Minister, he was in charge of sort of keeping the country together. But it’s a time of great turmoil, because James is the King of Scotland, and there’s a lot of resentment about that, and there was a promise of toleration for the Catholics, but my side, essentially, was very mistrustful of the Catholics, and convinced they were plotting with Spain to kill the king. It’s a wonderful part. I think it’s probably time I rang down the curtain on playing men behind the throne for a while, because I’ve done a lot of them. But it was too good to resist.”

The show reunites Gatiss with his Game of Thrones costar Kit Harington, who plays Catesby. Although maybe “reunites” isn’t the right word to use. “Well, you see, ‘costar’ with Game of Thrones is a very moot concept, because I’ve never worked with Kit before,” laughs Gatiss, whose other acting credits include the wonderfully weird sitcom The League of Gentleman and the upcoming special Christmas episode of Doctor Who. “I’ve only done four episodes [of Game of Thrones] and there’s about 17 units running at once. The likelihood of actually meeting someone is very small. So, I was delighted to work with Kit. I’ve met him a few times, and Gunpowder is his idea, actually. He’s descended from Robert Catesby, the character he plays. His middle name, in fact, is Catesby. We had a lovely time, but actually not very much together, because he is plotting it, and I’m uncovering it. And obviously, the two don’t really meet much.”

Gunpowder also stars Liv Tyler, who plays a wealthy relation of Catesby named Anne Vaux. “We have one big scene and we had a lovely time,” says Gatiss. “We have a funny connection because, many many years ago, she was married to an Englishman called Royston, as in Royston Vasey, the fictional town from The League of Gentleman. One night, I got a phone call, and it was Liv Tyler ringing from Los Angeles saying, ‘Can my husband speak to you? He’s a big fan.’ I reminded her of this. She’d totally forgotten it, but I’ve never forgotten obviously. It’s not the sort of thing you expect to happen on a Sunday evening. But she’s moved to London, and I think she just loved the script and wanted to do it. We had a really nice time, and I think she really enjoyed it. The Hollywood glamour was definitely not present in the car park in horizontal rain, but she didn’t complain.”

The first part of Gunpowder will debut Monday, Dec. 18, 10 p.m. ET on HBO, with the second and third episodes airing on the subsequent two nights. Watch a trailer for the show, above.