Fair City fans will see former Mrs Brown's Boys star Rory Cowan make his Carrigstown debut tomorrow night.
And it will bring back "happy memories" for Rory, who used to watch the soap with his late Mam on Sunday afternoons.
The 60-year-old actor, who played gay hairdresser Rory in Brendan O'Carroll's hit comedy, will play a very different role in the soap.
He is taking on the part of Molly's brother, John 'Bosco' Walsh.
In tomorrow night's episode, he arrives from Galway at the O'Briens' house and immediately becomes immersed in a storyline regarding Rose's dementia. However, Eoghan (played by Alan Howley) is left reeling when Rose returns with Bosco in tow.
Eoghan is shocked when he sees how serious Rose's condition is, and realises he must take responsibility for her care.
Fair City is a very new departure for Rory, who says he is "over the moon" with excitement to be in the show.
He also revealed that he can't wait to see what his character gets up to.
"The other cast members gave me a really lovely welcome when I called in to see them," he said. "I feel right at home in Carrigstown."
Rory became famous in Mrs Brown's Boys, playing Agnes's second son, until he left the hit show in the summer of 2017.
Rory said he used to watch Fair City when it burst on to our screens 30 years ago this month, but dipped in and out of the storylines as he toured with Mrs Brown's Boys.
"Myself and my Ma used to watch the omnibus on Sunday afternoons. I've lovely memories of those Sundays with my Mam."
It will be particularly poignant for the actor and comedy star, given that his mother, Esther, suffered from dementia for years.
He has said that doing drama is "totally different" to his comedy acting, but added "that's what I find so interesting about it".
He pointed out that in television drama, the timing and pace are different.
Fair City airs at 8pm on Sundays, Tuesdays, Wednesdays and Thursdays on RTE One.