Fair city producers are promising a special storyline set to "erupt" this week as it celebrates its 25th anniversary.
The show, originally set for a limited run, now has an average viewership of 500,000 people, four nights a week.
Executive producer Brigie De Courcy said she has been careful to keep the storyline under wraps.
"This week sees the huge end to a very big story that I think is going to be a bit shocking for the audience," she said.
"That is going to erupt this week which is fantastic and then we have the beginning of another story which is actually going to be quite explosive in another direction. So I would be watching on Wednesday and Thursday."
Cast and crew celebrated on the show's Carrigstown set at RTE in Donnybrook yesterday.