Following some wild antics when she first arrived in the village, Amy has been trying to remain on the straight and narrow in recent weeks after being welcomed into the home of Val and Eric Pollard.
However, in an interview with the official Emmerdale website, Halfpenny confessed that Amy's manipulative streak will return to the forefront of the soap in the weeks ahead.
She explained: "Don't get used to the nice side of Amy, or the side that seems nice.
"Remember what she was like at first, and remember how good she is at lying and scheming, because there might be a bit more of that coming up."
In the meantime, Amy's behaviour will take another downward spiral later this week when she seduces the village's bad boy Cain Dingle (Jeff Hordley).
Amy made her first appearance in Emmerdale last October.
> Click here to read our Emmerdale spoilers