David will soon find himself embroiled in a feud with his gran Audrey (Sue Nicholls), refusing to sign the salon back over to her when she asks him to.
As Audrey wants to take funds from the business to finance a round-the-world cruise with Lewis Archer (Nigel Havers), David fears that the charming con artist is back to his old tricks and refuses to co-operate. The situation soon spirals out of control with solicitors and police getting involved.
Speaking to Digital Spy about how fans might react to the story, Shepherd commented: "I would imagine they'd be on Audrey's side. I'm expecting people to say, 'What are you doing to your gran? Just let her be happy!'
"But if people come up to me and say that, I'll just explain David's point of view to them, and I won't let them go for about an hour! I'll try to really get it through their heads that Lewis is a bad guy and he will leave Audrey heartbroken.
"We don't know what's going to happen, but I reckon the viewers will be thanking me in the end!"
Shepherd added that David's mum Gail (Helen Worth) and wife Kylie (Paula Lane) will be backing him all the way.
"David's really against the idea, and so is Gail," he confirmed. "Kylie also has strong feelings on the matter - she fears that as soon as David hands the salon back to Audrey, then her inheritance will be gone. So Kylie's dead against the idea for money reasons, and she's acting like Lady Macbeth in this whole storyline, whispering in David's ear all the time.
"But it's not so much about the money for David - he just doesn't want his gran to get stitched over by the conman."
Coronation Street launches the salon war plot next Monday (March 26) on ITV1.
> Read our full interview with Coronation Street's Jack P Shepherd
> Read more Coronation Street spoilers and news