Jurors at Preston Crown Court were told she did not know why she did it, but her claims “eventually all came out” when her husband kept pressing her on the matter.
The woman said that Roache, who plays Ken Barlow in the ITV soap, made her perform a sex act on him while he gave her a lift home in his gold Rolls-Royce.
The alleged incident is said to have happened some time between June 1968 and September 1971.
She was one of four women who came forward to police after Roache was arrested and then charged last May with the rape of a 15-year-old girl in Lancashire.
Roache, 81, of Wilmslow, Cheshire, denies two counts of rape and five counts of indecent assault involving the five complainants aged 16 and under on dates between 1965 and 1971.
The woman told detectives that she had been sexually propositioned by another Coronation Street actor, Neville Buswell – who played Ray Langton in the long-running series – when he and Roache got her passes into Granada studios in Manchester.
On that occasion, the court has heard Roache was said to have sexually abused her older sister, who is one of the other complainants.
On a later date, she returned to the studios with a friend and Roache offered them a lift home in his Rolls-Royce Silver Cloud, jurors were told.
Giving evidence, the complainant’s husband described how he first realised that there was a connection between his wife, whom he married in the mid-1970s, and Roache and Mr Buswell.
He said: “What she used to do was doodle on the newspaper or any piece of paper.
“She was doodling ‘William Roache’ and ‘Neville Buswell’.
“I kept asking her, ‘Why do you keep doing that?’. She said, ‘I don’t know why’.
“This carried on for quite a while. It was like weekly she was doing it.
“Then it was there all the time. This is when it really came out. It was really getting on my nerves. ‘Why do you keep writing ‘William Roache’ and ‘Neville Buswell’?’”
He said he did not recognise the names at the time, only their characters in Coronation Street.
“Eventually it all came out,” he said. “She started crying.”
He said he had urged her to go the police but she did not want to.
The man eventually contacted the Sunday Mirror newspaper last March after seeing a television interview that Roache had given in New Zealand.
“I was absolutely fuming,” he said. “He made it out the girls threw themselves at him, that they were all easy and sexually active. And I know for a fact they weren’t and my wife wasn’t.
“I was extremely cross to put it mildly.
“He stated that there were girls or people suffering because of things they had done in a past life. They were being punished in this life.
“That really got my goat. It’s a ridiculous thing to say. I hope it’s true, because someone in this room is going to have a really bad life in the next one.”
He explained that he had wanted to “tell his story” rather than “sell his story” because his wife would not go to the police, but had since regretted it.
His wife eventually came forward on 1 May last year – the day it emerged that Roache had been arrested on suspicion of rape.
Earlier, she rejected a suggestion from Roache’s barrister, Louise Blackwell QC, that the incident in the Rolls-Royce did not happen. She said: “It did… it happened. I am just so sorry I have left it so long to come forward.”
In tears, she added: “I know I am telling the truth and the person you are defending knows I am telling the truth.”
A friend who was said to be in the Rolls-Royce told jurors that they were driving along when she saw her friend’s hand over Roache’s lap.
“I presumed what was going on,” she told the court. “I was a bit shocked and embarrassed. I turned to look out of the window.”
She said Roache then asked her to pass a cloth to him.
She said she could not recall how her friend’s hand had got there.
The witness said she did not say anything in the car and added, although it “sounds silly”, that she could not remember if she spoke about it with her friend when they left the vehicle. She did not tell her parents when she got home.
“Again, I was too embarrassed and ashamed,” she said. “It really was not the done thing to say in them days.
“I had never experienced anything like that before and I was quite young.”
The woman said she had not seen or spoken to the complainant in nearly 40 years when the police contacted her last year and she later gave a statement to detectives.
The trial continues.