Emmerdale spoilers follow.
Emmerdale star Jeff Hordley has spoken about Cain Dingle's controversial new storyline twist for the first time.
Fans were devastated last month as Cain betrayed his wife Moira by sleeping with his sister-in-law Ruby Fox-Miligan.
The surprise hook-up occurred while Cain was anxiously awaiting news on Moira's health as she underwent surgery to remove a tumour from her brain.
Cain was struggling to cope with his fears of potentially losing Moira if the operation went wrong, while Ruby was unsettled over the unexpected arrival of her father Anthony in the village.
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Asked whether Cain now regrets sleeping with Ruby, Jeff replied: "Yes, instantly, both of them did. It's a bit like one of those moments in a sitcom or a film, where two people wake up the morning after in bed and they go: 'Oh s**t, what the hell have we done?'
"But it's actually pretty instantaneous for them. As soon as they've had sex, they agree it was a mistake and that they can't ever say anything about this to anyone.
"It happened because they were both in such a bad place, but they know that's nowhere near a good enough excuse!"
With the truth bound to come out at some point, Jeff went on to discuss the likely reaction from Moira – as well as Caleb, who is Ruby's husband and Cain's brother.
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He said: "I think they know the jeopardy of this situation is humongous. His wife is not the forgiving type. And also, what the heck would she do to Ruby? She often reacts in the same way to Cain in these situations. She is volatile.
"Likewise, Cain doesn't want to jeopardise anything with his brother, because they're kind of back on an even keel. I think he really likes his brother deep down and they are starting to have a good relationship. So it's instant guilt and shame and thinking: 'Oh, good lord, what have we done?'"
Next week's episodes see Cain start to avoid Moira as his guilt is becoming too much to bear.
This makes the situation much worse, as Moira feels like Cain isn't supporting her while she waits for further updates on her health.
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Jeff said: "Cain is really struggling with it, and he's unaware that Moira's planning a surprise birthday party for him. When Caleb turns up to the house with Ruby, Cain's secretly looking at Ruby like: 'What the hell are you doing here?' And she's kind of looking back at him to say: 'I had no choice. Caleb wanted to come round!'
"So Cain, very quickly, makes up an excuse that he's got to go and look at a car that's somewhere else in the country, just to get out of the situation of being in the same room as Ruby, Moira and Caleb.
"He just goes and sleeps in his van for the night. He is trying to avoid any confrontation because he's feeling so guilty about the situation and what he's done."
Emmerdale airs on weeknights at 7.30pm on ITV1, and streams on ITVX.
