Little Dorrit, a major BBC One Dickens adaptation
Ruth Jones plays Flora Finching
Ruth Jones has the role of Flora, Arthur's (Matthew Macfadyen) rather overwhelming childhood sweetheart.
When Arthur reappears after a long absence, she fosters dreams of a romantic reunion - only to see them dashed by harsh reality.
The actress, who has made an immense splash as the co-writer and co-star of the BAFTA award-winning BBC Three sitcom Gavin And Stacey, was thrilled to be offered a part so far removed from the kind of roles she has been associated with in the past.
"I loved the fact that Flora is so different from any character I've previously played. It's wonderful to be able to have that variety."
So how would Ruth describe Flora?
"She has real energy and enthusiasm and love of life - I adore that about her. But she is also very complex. She is a sad person trying to make the best of the lot she has been saddled with.
"Life has stood still for Flora while Arthur has been away. She still dresses like a little girl, but now has lines under her eyes and has put on weight.
"She is now this rather matronly woman who is still a vision in pink. But I like the fact that she is not bitter about being left behind."
There is an affecting authenticity about the fact that Flora is unable to move on.
"That rings very true," muses Ruth, who has also starred in BBC One's other major autumn period drama, Tess Of The D'Urbervilles.
"When we go to school reunions, we still remember someone from a very young age. So when we see that they have in fact aged, it's quite a shock."
Ruth, who is currently working with her writing partner James Corden on a Christmas special of the acclaimed comedy, Gavin And Stacey, adds that she was touched by the poignancy of the situation in which Flora finds herself.
"She has loads and loads of unused energy. She has great passion but is not able to expend it. She's simmering with this life force that has nowhere to go. It's a heartbreaking story.
"Her life could have been very different," continues the actress, who has also gained a big following as Myfanwy, Dafyd's barmaid friend in Little Britain.
"She could have been very happy with Arthur, but it is a comment on society that they could never be together.
"Parental interference kept them apart. Flora makes the most of her fate, but there is still an underlying sadness that things have not turned out how she hoped. I'm sure that will strike a chord with people."
Very interestingly, Ruth adds, "something similar happened to Charles Dickens himself. He was in love with a childhood sweetheart called Maria, but on his 21st birthday they had an argument and went their separate ways.
"Years later, they met once again and Dickens was very disappointed by what had become of her. He has poured a lot of that experience into this part of Little Dorrit."
Ruth, who has also had major roles in Saxondale, Nighty Night, I'm With Stupid, Fat Friends and East Is East, closes by stressing that Dickens' writing continues to chime with people today.
"He creates such marvellous, vivid characters. He heightens them and sometimes people think, 'that's a bit over the top'. But he writes in such recognisable detail. As soon as you meet his characters, you understand them."