The Mystery of Edwin Drood is not your basic Dickens. Instead, it's a creepy, tense, psychological drama about John Jasper, a man with his eye on his nephew's fiancée. Trust us - you'll be shivering. And what's more, Dickens didn't even finish the novel - he died while he was writing it.
We caught up with Matthew Rhys - who plays John - to chat about the show and starring in something completely different from Brothers & Sisters...
The Mystery of Edwin Drood isn't one of Dickens' best known works - for people who don't know what it's about, could you give us a quick summary?
"I think it's basically the obsessional relationship between two... oh God, I have to be careful what I say and not give the end away! In very coarse terms, it's almost about drug addiction and stalking. If I'm talking from my character's point of view, then that's what I'd say."
You mentioned you don't want to give away the ending, but obviously there is no ending to the book. Has the writer Gwyneth Hughes definitely added an ending for the show?
"Yeah, very much so. Very much so. We give it a very definite ending, and it's fantastically justified from what's there originally. It's not a left-field ending that we've made up from nowhere. It's very cleverly justified by what Dickens himself had written."
So are you confident fans of Dickens will like the ending?
"Ooh, I wouldn't be so bold as to say that! I hope so, I hope so. Like I said, it's not that we've taken a punt and sort of plucked something. I think Gwyneth's done an amazing job of garnering a very specific ending that, as I said, is relevant to what's in there initially and originally. So it's all well justified I think."
It's quite a rare opportunity to take an established text and add something to it, isn't it?
"God yeah. Daunting and amazing in equal measure, I think, but a real opportunity for Gwyneth, and something I think she's done with great aplomb. She's taken the horns of it quite confidently and steered it to a fantastic ending."
So tell us a little bit more about John Jasper - what's he like?
"He's an incredibly troubled individual. You find him in the throes of narcotics dependency and unrequited obsessional love. The object of desire is his nephew's betrothed fiancée, so he has this incredible moral struggle and turmoil in trying to keep it in check, basically."
What can you tell us about the relationship between John's nephew Edwin and his fiancée Rosa?
"Through their fathers' doing, really, and their wishes in their world, in that old-fashioned way where dowries and arranged marriages were in vogue, they're sort of betrothed to each other by their parents' consent and wishes more than anything else, which at first seems to be on track for them and a good thing, but inevitably leads to an unravelling."
A character called Neville also turns up, doesn't he? And the relationship between Edwin and Neville isn't great, is it?
"It's not, no! Neville throws quite a large spanner in the works in that like most of the other males in the piece, Rosa very quickly becomes the object of his desire. But he doesn't have the same problem that John Jasper does, so he's immediately quite open and vocal about his feelings or what have you. So he becomes a very dangerous love rival to Edwin."
It seems like a very dark, tense show. Would you agree that's the case?
"Absolutely. That's what I was particularly attracted to in the piece. I love the fact that the BBC were unflinching in their attack on the darkness of the piece. Dickens himself can write beautifully about the human condition and does so very well on every side of the spectrum, so this one was incredibly dark and I love the fact that they followed that through to the end."
Was it fun for you, going to all those dark places?
"Absolutely! Especially coming off five years of Brothers & Sisters."
I was going to say this is a bit different from Brothers & Sisters!
"Yeah, enormously so! And at the end of Brothers & Sisters I said I wanted to do something very different, and wanted to get as far away from the part I was playing, Kevin. And John Jasper couldn't have been further!"
How are you feeling now about Brothers & Sisters coming to an end?
"Fine now. You know, the way in which it all ended was a bit of a shock. It was very abrupt, especially as we were sort of given... we were mildly assured that there would be a proper end to it, which there wasn't. It was sort of pulled very quickly and abruptly."
But as you say, it's given you the opportunity to do different things.
"Absolutely, which I'm very happy about. I got a lot out of Brothers & Sisters and learnt some incredible things and I think it certainly had come to a natural ending, so it was definitely time to move on. As I say, it was just the timing of it that felt abrupt."
So going back to Edwin Drood, why do you think Charles Dickens is still so popular?
"I think what I touched on earlier - he's like Shakespeare in that he has this incredible insight into the human condition. He writes incredibly well-rounded and three-dimensional characters that people relate to very easily. He's a great humanist and I think that's why he's lasted the test of time."
You mentioned that it was dark and tense - did you get on well with the cast? It must be quite difficult if you're filming a lot of dark scenes.
"Yeah. I'm certainly not one of those actors who remain in a dark place the entire time in order to be doing the scene. I sort of come in and out of it. It can be to the detriment of my performance sometimes! But we were all very lucky in that we had some great veterans of Dickens, like Alun Armstrong and Ian McNeice - the words fall out of their mouths as if they were born to say this stuff, so that influence was fantastic to have."
With a period drama you get the costumes and sets and everything - what was your favourite part about starring in one?
"It was exactly that, to be perfectly honest. Having done five years on a modern show, it was just great to do something completely different. Just that sort of Dickensian language, the different syntax and speaking in an English accent and doing a BBC Dickens - I think a number of actors want to tick that box, so I was very lucky to do so. It was all-encompassing, really."
What's next for you?
"I've just wrapped an ITV drama called Scapegoat which comes out at Easter, and then I fly to New York to start rehearsals on a play - Look Back In Anger. I'm looking forward to that!"
The Mystery of Edwin Drood begins on Tuesday at 9pm on BBC Two.