He laughs, “I think people had a wee look and went, ‘Oh that’s a shame,’ and turned the page. I thought I was going to be inundated with phone calls and stuff... it never happened.”
The 46-year-old, best known to TV audiences as the villainous Weatherfield businessman Tony Gordon and Casualty’s Dr Richard McCaig, plays Detective Superintendent Roy Grace in the stage adaptation of Dead Simple, which revolves around Michael Harrison, a man who has it all - great career, good friends and a beautiful fiancée.
When a stag night prank goes horribly wrong, however, he finds himself alone and staring death in the face. As time runs out, and the terror grows, will Grace solve Harrison’s mysterious disappearance in time?
For those unfamiliar with James’ DS Grace novels, the character can hardly be called a run-of-the- mill copper - one of the attractions for O’Brien, who has now read “five or six” of the novels in preparation for the role.
“What interests me about Roy Grace is that he has so much stuff going on in his life,” says the actor, still remembered in Scotland as River City’s serial womaniser Billy Davies.
He explains, “Something happened with his partner Sandy. Ten years ago she got up one morning, went out, and didn’t come back. She hadn’t taken her hand bag or her car keys and he is absolutely convinced she is still alive.
“I can understand that he would exhaust every avenue to find her, to the point that he has now got involved with mediums and people who have taken items of her jewellery to see if they can tell him anything.
“What I really like about the character is that he has now become kind of hooked on getting extra help from these other sources.”
Directed by Olivier Award winner Ian Talbot, Dead Simple is the second of James’ novels to be adapted for the stage by Shaun McKenna, and follows a successful tour of The Perfect Murder.
Joining O’Brien on stage are Holby City’s Tina Hobley, Jamie Lomas (EastEnders’ Jake Stone), Emmerdale’s Rik Makarem and Doctors’ Michael McKell. Completing the cast is Joshua Brown, Marc Small, Sarah Baxendale and Alan Freestone.
“We have a great cast,” says O’Brien, “Tina Hobley is just fabulous and Jamie Lomas has a great presence on stage, he’s a really exciting guy to work with.
“The thing is, at the start, you never know what to expect when you do a new piece like this, but you can actually feel audiences going along with you. When they gasp at the right places you know you are on the right track.
“And we’re getting a great mix of people. Peter James has a big fan base, and then you have the people who come along to see the folk off the telly.”
One thing fans of the books might pick up on is O’Brien’s appearance. In the first novel, Grace is described as ‘blonde and blue-eyed’. O’Brien isn’t.
“At the beginning, there was a little talk of his being blonde and blue eyed,” reveals O’Brien.
“Peter James asked me ‘What are you going to do about your hair?’
“I’ve got very dark hair, well, greying dark hair now, and I replied, ‘Well, what do you want me to do about my hair?’
“But it just would not colour. It turned orange, so that was a no, and the director didn’t want me to have a wig, so we just had to use a bit of creative licence.”
O’Brien’s return to the stage comes after an impressive 13-year run, during which time he was scarcely off TV screens.
“For 13 years straight pretty much, with just the odd couple of weeks hiatus, it was really just one of those crazy runs,” he agrees. “I think it came to a head with Coronation Street.
“That was one step too far for me in the respect that Tony Gordon was a popular character, all the writers wanted to write for him and, of course, at the time I didn’t realise what’s happening.
“You get all this work, all these scenes to do the next day, and you can’t possibly be on top of all the 15 scripts every other week, so you just kind of go along with it.
“I only intended to do two years in Corrie, they asked me to do another. I couldn’t even tell you I’d done it. It went that quick.
“Before I knew it, I had done three years and more than 500 episodes - then that’s all people seem to remember you for. It was such a high-impact role.
“I thought I just need to get back to work... back on stage, a completely different skill, which is actually every actor’s first love because it’s what we trained for - we didn’t train for telly, we trained for the stage.”
And it was here in the Capital, that O’Brien made his professional stage debut, appearing in Frank Dunlop’s Festival production of Treasure Island, in 1990.
“That was the job that got me my Equity Card,” he recalls, “ and it will be lovely to be back.”
Dead Simple, King’s Theatre, Leven Street, until Saturday, 7.30pm (matinees 2.30pm), £14-£29.50, 0131-529 6000