The Shawlands-born actor is set to star in this year's Pavilion Theatre panto, Pinocchio, playing Honest John The Fox.
"I was brought up in variety theatre tradition," he says, sitting in the Pavilion stalls.
"I used to come here with my parents and I remember seeing Glen Daly perform when I was 11.
"And I can also remember coming to see the Francie and Josie Christmas Show.
"Now, I can't believe I'll be on this incredible stage."
He adds: "Glasgow is my home town, and this is the first time in all these years I haven't had to travel to go to work at Christmas."
His success is well deserved. Iain Gouck has funny bones.
"At Sunday school, I'd always be asked to get up on a chair and sing," he recalls.
"At school I was part of the drama club and before you knew it, I had joined the am-dram Pantheon Club in Glasgow. And I loved it."
Iain may have harboured dreams of becoming a full-time actor, but they were not attached to any real expectation.
When he left school he went to work for a travel agency; indeed, in his 'resting' moments he still helps people find their perfect holiday.
However, it was while appearing with the Pantheon Club that Iain enjoyed a life-changing moment.
Comedy Unit boss and Rab C. Nesbitt producer Colin Gilbert had been tipped off about this very funny young man, and came to see Iain in La Cage Aux Folles.
"A couple of days later, someone from the BBC with a very pucker voice called me. I thought it was a wind up when they said they were interested in me.
"I was excited - but terrified. I said to the voice on the phone; 'Look, I could get really excited here, so if this is a wind-up please tell me now'.
"But it wasn't. It was brilliant, and Colin was very good to me. I appeared in six Rab C. Nesbitt's and two series' of Mr Wymi.
"And I soon began to get professional theatre work and interest from STV."
Iain has played comedy for most of his career.
"Some people think I'm funny. I hope it's because I've got good comic timing, which I studied while appearing with the likes of Rikki Fulton, in I M Jolly, and Jimmy Logan.
"There is much a metre to comedy dialogue as there is to singing."
Iain is a portly chap. Did he ever worry that losing weight would impact upon his comedy career?
"Yes, I have worried about that. You can fit into funny roles when you're big. Although my doctor however took a different view and I've actually lost five stones in the past four years. I had to do it. And it means I can be more physical on stage."
Iain appeared in panto in Kilmarnock for nine years, with Anne Fields.
"Then I went to the Ayr Gaiety, which is a smashing wee theatre. From there I moved to Motherwell and Inverness."
Ah, yes, Inverness. The scene of one of his most demanding panto experiences.
When Iain signed to appear as the Dame in Sinbad, he assumed the panto would be staged at lovely, warm, Eden Court Theatre as always.
Oh no, it wasn't. Because Eden Court was being renovated, Iain and the cast were relocated to a drafty tent.
It was a giant tent of course, a big top. But it was still a tent. And in the middle of the Inverness winter, the inside of the tent was colder than the Wicked Stepmother's heart.
"A huge stage and seating was built inside. And industrial heaters were brought in to stop the actors and the audience freezing to death.
"But the diesel-driven industrial heaters were so noisy you couldn't be heard, so they were switched off during the show.
"As you can imagine, it takes half a second for the heat to leave a canvas tent."
Sinbad's mammy wore countless pairs of vests and underwear.
"The problem with that was while performing in so many layers you sweated buckets. But as soon as you stepped off stage you cooled down and began to shiver.
"It was a nightmare. And after the show, we got washed in a portable cabin a hundred yards away. In cold water."
He adds, grinning; "To give you an idea how cold it was, the brakes on my car, which was parked outside, seized because of ice.
"What was amazing is none of us died. I guess the magic that is theatre protects you from illness."
But the trials and tribulations he's endured over the years have been worth it.
Now, he's at the Pavilion. And set to be as warm as the Fairy Princesses' glowing smile.
"This is an incredible theatre," he says, gazing around the 1600-seat auditorium, his voice emotional.
"I can't quite believe I'm here. I'm the oldest newcomer in town. And it's wonderful."
n The New Magical Adventures of Pinocchio, Pavilion Theatre, November 27-January 19.