“Keeping Faith” has become one of the most popular shows in Britain. Does that surprise you?

Yeah. You’re up against huge, huge juggernauts that don’t have to fight to be anywhere, have great budget, great promotion, great marketing. This was a scrap from Day 1. We had no money. The car I used in the show is my director’s car. [Laughs.] It came close to Faith being a barrister on a bike.

And then it went on iPlayer and just exploded without any marketing or promotion. That’s unheard-of. We made the most of what we had, but we were wealthy in story. We were wealthy in passion and in talent and in the need to prove that we can make something like this with very little but a great, great script and a great team.

Faith has become a lifestyle icon with her yellow rain slicker and bright blue coat, and the “Faith bun” just might rival “The Rachel” from “Friends.”

To think that people are doing the Faith messy bun and the bangs and wearing these coats and everything means a great deal to me — because it means that everyday brilliant women are feeling good because it makes them feel strong like Faith. They think they’re connected to me but I don’t think they realize how much I feel connected to them.

To an outsider, the Welsh language seems unfathomably knotty. How daunting was it to learn?

I didn’t even know there was a Welsh alphabet. The producer came over and sat down in front of me and said, “Well, let’s have a read.” And I remember it being about 9:30 in the evening, and I had hives all over my neck and my chest with nerves. I was so, so stressed out because I’d refused the job so many times by trying to tell them that I didn’t speak Welsh, and then I had to prove to them that I actually really, really didn’t. So when she said to read, I said, “I don’t know if I’m holding the page the right way. What do I do?” And I literally could see the color draining from her face.

You shot each scene first in English then in Welsh. Had you learned the language well enough that the emotions came naturally, or did you do it by rote?