The one-off programme will document the origins of the ITV soap, as creator Tony Warren fought to get it on air.
David Dawson, who plays Warren, told The Sun that he had viewed the show with the Corrie veteran.
"We watched the drama together," he said. "Bill is a lovely man and had tears in his eyes at the end."
He continued: "You forget it has been 50 years of his life and a little bit of it is being shown on the screen."
Roache's son James, also currently appearing in Corrie as Ken Barlow's grandson, will play his father in the drama.
The Road to Coronation Street airs tonight at 9pm on BBC Four.