Emmerdale fans have floated a new wild theory on the truth behind Cathy Hope's recent erratic behaviour on the ITV soap in the last few weeks on the Dales.
The ITV soap viewers think the teenager could be harbouring a secret relating to her paternity, with some saying Bob Hope may not be her real father after all.
Bob, who is father to twins Cathy and Heath, initially did not want to have more children after the death of his daughter Dawn.
The twins’ pregnancy got off to a rocky start when Bob’s late wife Viv Windsor had planned to undergo an abortion – before Bob intervened and stopped her at the last moment.
Bob went on to father the twins with Viv and Paddy Kirk delivered them in 2007, before Viv was killed off in a fire alongside Terry Woods (Billy Hartman), who was attempting to rescue her when an explosion engulfed the Post Office in 2011.
Cathy was recently seen breaking down on the ITV soap, prompting her twin Heath to take her aside and voice his concern over her unusual behaviour.
Cathy admitted to feeling “scared” at times before the feeling passed, saying: "It’s like this thing comes down and I hate everything and I’m scared. And then it’s gone."
However, fans now think there could be a big twist ahead and it will be discovered that Bob is not in fact the biological father of the twins.
Some have even suggested that Cathy and Heath could have different dads, which although extremely rare, is possible.
Taking to Twitter, one fan wrote: “I think the twins have different Dads and she will need to go for tests and find out Bob isn’t her biological dad just a thought.”
Another fan replied in agreement and even suggested a major potential twist as they wrote: "Agree and paddy is her dad!!"
One fan chipped in: "Different dad from Heath even though they are twins. Very, very rare and not been covered before."
A fourth said: "That's the next story line she isn't bobs daughter."
However, other fans think that Cathy could be suffering from bipolar disorder or seasonal affective disorder, whether the weather drastically changes a person's mood.
Cathy's storyline has been teased to be a big one, so whatever she is hiding, it is set to rip apart the Dales in major scenes on the ITV soap next week.
Emmerdale airs weeknights at 7.30pm on ITV.
Got any theories or thoughts on the storyline? Let us know in the comments section below.
