The actor, whose previous screen credits include Merlin, Game of Thrones and Star Trek: Voyager, arrives on the Channel 4 soap next month as Brendan and Cheryl's evil father Seamus.
Pictured: Fintan McKeown as Seamus Brady.
Viewers have heard lots about Seamus in recent months as this year's series of Hollyoaks Later featured the shocking revelation that he sexually abused Brendan (Emmett Scanlan) when the show favourite was a child.
Brendan's turmoil over his troubled past was further explored when he attended counselling sessions with Cheryl (Bronagh Waugh) on the main 6.30pm show.
Speaking of his new role, McKeown commented: "This is my first appearance in soap opera and I hope I can bring something unique to the style and format of the show.
"I enjoy working with everyone on set, especially my on screen family, Emmett and Bronagh. I can't wait for all the drama that will inevitably ensue."
Once Seamus makes his arrival in the village, viewers will be left to wonder whether Brendan can finally stand up to his father, or if he is doomed to face more nightmares and torture.
A Hollyoaks statement added: "Brendan's sister Cheryl is unaware of the very different childhood her sibling had, so could this be an opportunity for the truth to finally surface? Or will there be more wrongs before there can be a right?"
Hollyoaks airs Seamus's first scenes on Thursday, December 20 at 6.30pm on Channel 4.