The pair grow closer in the coming days, but when Katy tries to stay loyal to boyfriend Chesney, a rejected Ryan (Sol Heras) turns his attention to her friend Steph instead.
Unhappy with Ryan's new romance, Katy turns ruthless as she plots to break the pair up.
Foote told Soaplife: "Her friend Steph makes a play for Ryan and Katy gets really, really jealous. She actually goes out of her way to ruin it and try to split them up, which isn't very nice.
"[Ryan's] the kind of person who won't wait around for someone when he can have whoever he wants. When Katy told him they shouldn't be doing this, he said that's fine - then went off with Steph instead. When he realises that Katy's been trying to split them up, he asks her what her problem is.
"She suddenly snaps and tells him why she did it - and this leads to a big kiss. Katy and Chesney never really shared any passionate kisses, it's only ever really been more of a peck. But Katy and Ryan are pretty full-on. It's something she's never experienced before."
As Katy begins to give in to temptation with Ryan, she is completely unaware that Chesney is planning to propose to her.
Asked how Katy would feel if she knew this, Foote replied: "I think she'd be absolutely devastated. Deep down she does love Chesney and knows that she should be staying loyal to him. But she's found in Ryan something she hasn't been getting from Chesney."
Pondering whether Katy would marry Chesney, Foote concluded: "Perhaps before this she would have been ready, but now I think she feels differently. Maybe she needed Ryan to come along to make her realise that she wasn't that happy after all."
Coronation Street airs these scenes on Monday, March 11 at 7.30pm and 8.30pm on ITV.
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