The unlikely pair will soon embark on a shock fling, throwing Peter's future with Carla Connor into question.
Speaking about the story for the first time, Gascoyne told TV Times: "Peter is really lustful for Tina. I think he almost sees a younger Carla in her. He found it really exciting when she put up a fight against Tracy. He admired her spirit and started to see her in a different light.
"Peter adores Carla, but he feels a bit neglected. He even tells Tina that, despite everything Carla has done for him, he's still not happy. Peter knows it's not a good idea to be around Tina, but he really doesn't want to stop seeing her."
The romantic spark develops after Tina (Michelle Keegan) agrees to help out Peter by looking after his son Simon.
Carla (Alison King) is too busy planning her and Peter's wedding to notice that anything is amiss, but with the big day looming, the forbidden attraction could have major consequences.
Gascoyne added: "Put it this way, Peter Barlow and a wedding is bound to spell disaster. It certainly won't be dull. Whatever happens, it will be brilliant. Peter's had a good go at weddings - this will be his fifth. That tells you something."
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