Exclusive: In Pictures: The 'McDean' affair exposed
The 'McDean' storyline has dominated the Chester-based soap for just over seven months and next week, the boys' secret is finally outed during Craig and Sarah's engagement party when Sarah finds the pair in bed together.
A show source told DS: "John Paul's sick of all the lies and decides enough is enough. He sends a text from Craig's phone asking Sarah to come upstairs to see him."
They added: "Safe in the knowledge that Sarah is on her way, JP sets about seducing Craig. When she walks in, she can't believe when she's looking at..."
These scenes are due to air on Monday, September 10 at 6.30pm on Channel 4. The fallout of the revelation leads to Guy Burnet's final episode with the soap which will transmit on Thursday, September 20.