Hoole actor Ian Puleston-Davies speaks candidly about his obsessive compulsive disorder (OCD) in a new BBC documentary that airs tonight (April 3).

OCD - An Actor's Tale will give a rare insight into the former Coronation Street actor's struggles with the 'all encompassing' condition, which he says he has had since he was a young boy growing up in Flint.

In the documentary, which airs on BBC One Wales tonight at 8.30pm, Puleston-Davies is seen returning to his former school Ysgol Gwynedd for the first time where he looks at a picture of himself that he now describes as 'OCD captured in time'.

"I'm waving, but I'm the only one not looking at camera - my eyes are down - probably worrying about some small thing," he reflects.

The 58-year-old, who played builder Owen Armstrong on the cobbles for five years until 2015, says one of his biggest fears is 'sitting down too quickly and cracking my coccyx', reports our sister paper The Mirror.

Ian Puleston-Davies in a scene from Coronation Street
Ian Puleston-Davies in a scene from Coronation Street

"If I'm in a restaurant, I can't just sit down straight away. I have to measure the distance between my coccyx and the seat," he said.

"I can't be bobbing up and down ... I'll look like the crazy man in the restaurant.

"I have this smokescreen of deceit where I'm pretending to sit down but I'm actually going 'have I got my keys? I must have left them in the car' ... 'Are you happy here, we can always sit there'.

"All the time this juggling is going on ... I'm actually measuring the distance between coccyx and seat."

He adds: "If you don't indulge the voices, the noises in your head, you are under extraordinary stress which won't go away and believe me that noise can and does get very, very loud."

In 2014, he spoke of the difficulties of being on the set of Coronation Street with OCD.

"If I have a scene in the Rovers Return, I worry that I’m going to cut my lip or chip my teeth on the glass, so before we rehearse I have a little ritual where I check the glass with my finger to make sure it’s not chipped, then wipe it to ensure it’s clean and check the contents to make sure there are no foreign bodies in it, then practise taking a sip and swallowing.

"If I waited until we began filming, my OCD – that voice in my head – would say ‘It’s stained’ or ‘You’ve just chipped your teeth.’

But luckily he had understanding co-stars, explaining: "The other cast members know about my OCD and are very supportive."

OCD - An Actor's Tale airs on BBC One Wales tonight, Monday April 3 at 8.30pm