Little Dorrit, a major BBC One Dickens adaptation
Matthew Macfadyen plays Arthur Clennam
Matthew Macfadyen plays Arthur Clennam, the mysterious figure whose return from overseas to fulfil his dying father's last wish completely transforms the lives of the Dorrits.
The charismatic leading actor, who has gained a huge following on the small screen as Tom in Spooks and on the big screen as Mr Darcy in Pride And Prejudice, says he had no hesitation in accepting the role of Arthur.
"This story really blew my hair back," he grins.
"Then when the rest of the casting came through, I couldn't believe my luck. I've been in some sexy casts in my time, but nothing quite like this!"
Matthew, who has also starred in The Way We Live Now, The Project and Warriors, goes on to outline the role.
"It's quite a challenge playing Arthur. At first, I was worried that he's merely the glue that sticks this story together.
"I didn't want him to be drippy or overly passive or always on the back foot. There's always a concern as an actor that you'll be boring unless your character is swinging from a chandelier.
"But once I got into the part, I realised that Arthur is really quite sympathetic.
"As it went on, I discovered him to be richer and richer. He's got genuine depth.
"He's getting on a bit and he's still suffering the after-effects of his awful lonely upbringing at the hands of his terrible mother and father. He's emotionally bereft, and I think people will really feel for him."
Matthew reckons that "audiences will also be intrigued by the mystery element to his story. His father has given him a watch which has this strange message inside and Arthur feels a family responsibility to solve it. It's an old-fashioned whodunit, and it's frightfully intriguing."
As the title indicates, at the heart of the piece is a deeply moving relationship between Arthur and Little Dorrit (Claire Foy).
"That relationship is lovely," Matthew beams.
"It's very poignantly drawn and so true to life about male-female relations. He has no clue that the person who loves him is standing right in front of him.
"Audiences will be shouting at the screen, 'come on, Arthur, you twit! Open your eyes!'"
Matthew relished his scenes with Claire.
"She's totally brilliant. It's a huge task for anyone, but for her to pull it off on her first or second job out of drama school is just amazing. She's also completely down to earth. She's very good news."
The actor was equally excited about appearing opposite one of his idols, Sir Tom Courtenay, who plays Amy's father.
"I did a fair bit with Tom. You can learn so much from watching him - he's an actor to his fingertips. I loved working with him.
"In fact, this whole project has been bliss!"