'Emmerdale's Zak Dingle will pretend his cancer has returned.
The unemployed poacher's mental state has been declining ever since he assaulted his own son Cain and left him for dead and rather than admit he has been diagnosed with a mental health disorder, Zak will tell his wife Lisa his testicular cancer is back and is now terminal.
Steve Halliwell - who plays Zak - told Soaplife: "He's half aware of what he is doing but reality and fantasy have become very blurred. He's feeling so unwell he's convinced they've missed something. He gets very angry when the doctor refuses to do more tests and security has to be called.
"He's mentally unbalanced and digging himself in deeper. He says the cancer's gone too far for any treatment. It's just to shut everyone up, but once he's said it he can't retract it.
"He's just saying anything that comes into his head. And he's heaping more stress on himself with all of the lies."
Zak's fragile mental state will get progressively worse over the next few weeks and he will even imagine Cain (Jeff Hordley) has come to kill him.
Steve added: "He has no idea where he is. He starts fantasizing and talking to people who have died. He's frightened of everything. He gets progressively worse and is convinced that Cain is on the moors looking for him because he wants to kill him."