The Ken Barlow actor's two sons, Linus and James, are joining the show - as the son and grandson he never knew he had.
Linus - whose mother was Bill's first wife, actress Anna Cooper - will play Ken's homophobic son Lawrence. James will play Lawrence's gay son who is also called James.
"Sara would've loved my sons being on the street with me. I feel she's very much still with me," he told The Sun "In my understanding she is still alive."
Roache also admitted that he would have liked to have seen Blanche Hunt's reaction to the storyline. Actress Maggie Jones passed away last December.
He continued: "It would have been wonderful if Blanche were here.
"She would have referred to Ken as some un-neutered tom cat, saying, 'Another son! How many more are coming along?'"
On the upcoming storyline Linus said: "I'm a little indifferent about my own son. Ken picks up on that and meets my son who is gay. I'm very intolerant of his sexuality."
Roache added: "Lawrence is all the things I'd want a son to be - cultured, sophisticated, handsome of course. He's thrilled to bits. Then comes the thing... he won't talk about his son."
> Linus Roache: 'Dad is my inspiration'