Emmerdale star Claire King revealed she worked out who was poisoning Kim Tate, despite soap bosses trying to keep it a secret from her.
Claire said she discovered the culprit before bosses told her "through powers of deduction".
As the storyline went on and suspects were whittled down, Claire managed to figure it all out, while bosses deliberately kept the truth from her and other cast members - reports Mirror Online.
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She explained that producers feared the cast would film things differently if they knew who was to blame and who was innocent.
Claire said: "We weren't told who the poisoner was at the start because they thought we might deliver lines in a sort of way, or give some clues away.
"So no, not at all but through the powers of deduction we found out anyway."
A mystery character has been drugging Kim's brandy for weeks, leaving her unwell and confused.
She soon realised what was happening, and has been faking symptoms of being poisoned while setting a trap to catch the person out to get her in the act.
But things are set to take a deadly turn when Kim's found lying lifeless on the floor, with a bodybag beside her, with the police arresting Will Taylor.
Claire promised that the culprit, whoever they are, was not an obvious choice.
Claire said it would come as a surprise and said: "Yes, because there are twists and turns in it so I think when it comes out, it doesn't sound as obvious as how I've just told you now.
"I think it will be a shock at the end of it."
On the Succession styled storyline with the different suspects in the frame, Claire confessed she worried it sealed the end of Kim.
She said: "I thought, 'Oh great, but if there's a succession does that mean I'm going?'."
