Charity currently has no idea that her husband Jai is the father of Rachel's unborn child, still blissfully unaware that they had a one-night stand earlier this year.
Speaking to The Sun about how Charity will feel when the truth comes out, Atkins commented: "I'm really intrigued. I don't know how they will write it. I think Charity will be very shocked that she'd not worked it out, because Jai has essentially been leading a double life.
"That's been going on under Charity's nose and yet she absolutely has no idea. Usually she doesn't miss a trick. She's a great detective. It's going to be one hell of a revelation. I can't wait to play it."
Asked what keeps Charity interesting for her to play, she replied: "She's got a constant curiosity as to what she could make herself. She loves to learn. She's quite a bright cookie. And even though she makes mistakes she learns from them."
Chris Bisson, who plays the role of Jai, recently confirmed that his storyline with Rachel has a long way to go.
He said earlier this week: "That continues to build. We've got a little bit of a break from it while we get through the live episode, then we're straight back into it for Christmas and the New Year. But that's a long-running story, so watch this space."
Emmerdale continues tonight (October 18) at 7pm and 8pm on ITV1.