Chris (Will Thorp) has recently been pretending to be seriously ill in an attempt to win back Cheryl from Lloyd Mullaney, keeping quiet over the fact that his brain tumour has actually receded.
The game is up for Chris at the end of next week when a doctor inadvertently reveals the truth to Cheryl at the hospital. However, by this point, Cheryl has already dumped Lloyd (Craig Charles) in favour of Chris.
Quin-Ankrah told All About Soap of the plot climax: "She's shocked to discover the tumour has been shrinking and that he should make a full recovery. She's pledged her future to him based on his illness and it's been a huge lie. She can't believe Chris could sink so low.
"The thing that appals her the most is that he's lied to Russ - she thinks that's unforgivable. At that point, Cheryl knows she's lost everything and has made a huge mistake."
The actress added that she believes Cheryl is not a bad person at heart despite her recent behaviour.
She said: "Cheryl is a good person really. I know that she's deeply upset Lloyd, but she was lied to herself and, as a result of that, she's been left with no-one in her life."
Coronation Street continues tonight at 8.30pm on ITV1.
> Coronation Street Chris lie is disgusting, says Will Thorp
> Coronation Street Chris, Lloyd showdown 'won't be pretty'
> Coronation Street star Will Thorp excited over life after soap
> Coronation Street Lloyd has a breakdown, says Craig Charles
> Read more Coronation Street spoilers and news
Watch a video preview of tomorrow night's Coronation Street double bill: