Coronation Street’s Tim Metcalfe is terrified he has cheated on his wife with Gina after a drunken night.
Tim, played by Joe Duttine, has been struggling to get into the festive spirit with Sally (Sally Dynevor) behind bars.
In upcoming scenes in the ITV soap, Gina Seddon (Connie Hyde) invites him over and offers him a shoulder to cry on while he drowns his sorrows.
When they wake up he fears they have slept together, and Gina does little to alleviate his suspicions.
Duttine said: “Tim is utterly devastated that he has done something like this. He can’t believe it.
“There will be a lovely little thing with Faye where he breaks down about it.
“The thing about Sally and Tim is that they’re monogamous, they love each other and are loyal to each other.
“They don’t go off and have affairs – there are other things they can do with those characters. So he’s utterly devastated to think that he has cheated on his wife, as mad as she is.”
However, Tim does come to realise that things may not be as they seem.
“His loyalty shifts between the two,” said Duttine.
“At one point he thinks that Sally has had this affair and he doesn’t have this perfect life. While he’s believing that, he’s hanging out with Gina a lot.
“They go to county matches together, play darts and form this friendship. She’s providing him with stuff that Sally never had – they sit and watch zombie films together and stuff like that which Tim really likes.
“And then this happens and he starts to see that she has been quite calculating.”
The star promised a “very eventful Christmas Day in the Metcalfe house”.
“I think it’s going to be good viewing,” he said.
“I’m really looking forward to being allowed to do some interesting stuff. It’s not the happiest house on Christmas Day.”
Coronation Street airs on ITV.