Natalie Dormer loves getting dirty, wet and cold--at least for her art.

If you've seen last week's episode of BBC America's amazing horror series "The Fades," you know what I'm talking about. (If not, stop reading! Spoilers!)

Dormer's character Sarah, an evil-fighting angelic who already had died and become a Fade (a ghost), decided to eat human flesh so that she, like the evil Fades she wants to stop, will be reborn as a flesh-and-blood human. Call it the messiest undercover mission you can imagine.

"Yeah, being swamped in goo all day, freezing cold goo," she told me during a phone interview. "I said to the props guys, 'Could you not have warmed the goo a bit, could you not really?'

"I was in that bath--[laughs]--I was in that pretty much naked all day, but it was very satisfying."

The Season 1 finale premieres at 8 p.m. Feb. 18, and you can expect to see more rebirths and other shocking moments as teen angelic Paul (Iain De Caestecker) tries to foil Fade John's (Joe Dempsie) plot to destroy humanity.

Dormer was impressed with not only the muck that she was mired in for her rebirth scene, but all the creepy effects that have made the series such fun to watch.

"It just goes back to what I was saying [from Curt: in our earlier interview here]," she said. "The production value, what was created is filmic. What we created for a little BBC show, sequences like [the tub scene], I think we can be really proud."

Dormer talked more about Sarah's rebirth scene, how she caught a cold and the goo--which was based on a cow's stomach. Also, watch the video preview of the season finale below, and the BBC clip about the rebirth scene above.

I have to ask how much fun it was to roll around in that goo in the tub.
[Laughs.] I got very ill. [Laughs.] But Jenn [Murray], who plays Natalie, in her cocoon had to do something quite similar and she was in this awful bunker underground. At least I was in a nice cozy house with a hot shower next door.

As an actor, you take your brain to a very extreme place. I love doing stuff like that; I love taking myself out of my comfort zone. I couldn't believe what they designed; I thought it looked amazing. And the way Tom Shankland, the director of the second half of the series, directed that. Tom's directorial sort of archive would be kind of more thriller- and horror-esque than Farren [Blackburn], who kicked us off.

I just loved the way Tom shot that sequence. But it was a really grueling, trying day. And Johnny Harris [who plays Neil], when he's in the scene talking to me and watching me and crying and getting really upset, I think we all came away from that day with a real sense of achievement.

Hopefully, God willing, if we went to a second series, which I think it deserves to because you've got so much of the story foundation laid, hopefully there would be the confidence and the support for us to do more extreme sequences like that and really push the bar, because I think the audience will respond to them. [Note from Curt: No official word on a second season yet.]

The sound effects and the look every time someone is reborn, they are so vivid. It's almost like you can smell it, like you're there as a viewer. But, yeah, I was curious about how long you actually sat in that tub.
Yeah, the whole day on and off! [Laughs.] I just kept getting in and out and having a hot shower to warm up and go back. I'm not kind of convinced how I got the cold. I don't know if I got the cold because I was in cold goo or from Johnny Harris. He was definitely sick--[laughs]--so I don't know whether to blame Johnny Harris or the goo.

You were in the muck so long; you're not claustrophobic, are you?
[Laughs.] It's just amazing; I think like the art department based the cocoons on a cow's stomach. They did the design of that sort of plaquey, almost veiny-like sack. They did so much detailed design work and I think, in the end, it was based on some kind of offal stomach or something.

It was really bold, quite unsavory stuff, but I think that's why so many people have responded to the show, because some of the choices that were made in the art design and in the acting, hopefully, and definitely the writing, are brave. We all really aimed to be brave about it and scare ourselves and other people with how far we were prepared to go in the detail.

So I'm glad if you say that that comes across, because that really was the aim.

SEASON FINALE PREVIEW