Next week's episodes see Chas and Katie (Sammy Winward) decide to host a double wedding reception, as their respective nuptials with Dan Spencer and Declan Macey are both taking place on the same day.
> 'Emmerdale' 40th anniversary - full coverage
However, Pargeter told STV that the arrangement will lead to tension as the soap's 40th anniversary week begins.
Pargeter commented: "The wedding is very much the rich versus the poor - of course Katie and Declan are getting married as well, lord and lady of the manor with all the money, versus the poor people. And I'm even poorer because I'm being blackmailed by Carl and having to find the money for that.
"So the budget for our day is getting smaller and smaller, but it's about [Chas and Dan], it's about their day and it's about them declaring their kind-of love for each other."
She continued: "Chas has a big fall-out with Katie just before the ceremony, so not all is cool in the church!"
Meanwhile, most of Chas's loved ones are currently unaware of her recent affair with Cameron Murray, the partner of her niece Debbie.
Asked whether Chas would reunite with Cameron if he dumped Debbie, Pargeter replied: "Who knows? It's a soap. I don't know if they're meant to be together, I don't know if they would be together. I think she's truly supposed to be with Carl, but I'm not the writers!"
Emmerdale launches its big birthday week on Monday, October 15.