Coronation Street's Jim McDonald looks set to return to Weatherfield with a muscle-wasting condition.
The ITV soap are to explore the issue when the no-nonsense convict - played by Charles Lawson - makes his cobbles comeback, nearly two years after he told son Steve McDonald (Simon Gregson) he could have genetic disorder myotonic dystrophy.
Series producer Kate Oates said: "We played a story 18 months [ago] where it seemed like Steve might have inherited a genetic disease from his dad, but no one went to see Jim to ask if he was OK.
"We have a great story to play with that."
While Steve received the all-clear after tests to see whether he had the condition, viewers were not informed about Jim's prognosis.
Charles recently confirmed he will reprise his 'Corrie' role for a short stint this year and then return again in 2019, and Jim - who is currently in prison - is not going to be best pleased with his family when he heads back to Weatherfield.
Speaking to RadioTimes.com, Kate added: "We have some amazing stuff with Jim McDonald. He's going to be coming back with a lot of resentment because of what Steve did.
"From Jim's point of view, he's been rotting in prison and no one cares."
Jim was last seen on the cobbles in 2014 when he illegally sold Peter Barlow (Chris Gascoyne) alcohol in prison, and his sentence - originally for the robbery - was extended after he used a mobile phone to phone his wife Liz McDonald (Beverley Callard).
Jim was seen threatening Steve with revenge after his son grassed him up to the police when he realised his father was trying to use him to get back with his mother, Liz McDonald (Beverley Callard).
Charles revealed last week his 'Rebus' theatre commitments had put paid to him being back on the cobbles full time this year.
He said: "They wanted me back full time this year but I couldn't do it as I am doing 'Rebus' on stage, and a thriller.
"I'm going to film a bit but then will be back again next year."