BIG Bob walks into the internet café and the realisation hits like a punch in the belly he isn’t any more.

Not big, that is. He’s Medium Bob. Better Bob. Type 2 Diabetes Clear Bob.

But that’s not the only change actor Tom Urie who has grown out of, in reverse fashion, his River City character.

Paisley-born Tom, at 49, is no longer the depressive who gave himself five years – tops – to live.

Such was his self-loathing, his need to consume huge amounts of food, his melancholia, after he was written out of River City he cut himself off from family.

He even slammed the door in the face of Christmas, a time he loved, choosing to pull a duvet over his head and wish the Baby Jesus had never been born.

“I couldn’t bear to let my family see me as I was,” he recalls of the time three years ago. “I closed the curtains and went to bed.”

He adds, grinning; “But feeling this bad didn’t put me off my food. I had a Fray Bentos steak and kidney pie for my dinner.”

Tom knew however to give up on Christmas was to give up on life. A doctor recommended anti-depressants which helped steady the ship. “Reaching rock bottom has made me realise don’t want to go back to the point where I couldn’t stand up from a chair, or get in a car.”

He tackled the weight problem. Dieted. Exercised ‘till he was blue in the face. It worked. He’s lost 19 stones.

When we meet in a trendy Glasgow café he won’t have a wee snackette. Just a black coffee. How heavy was he in the first place? “I don’t go there,” he says.

Why? He won’t say. But he must have been big. Around the 30 mark. That doesn’t matter. What matters is he’s now a decent size and he’s going to the gym three times a week.

“I was in a plane last month for the first time in years, and I didn’t even have to ask for the special seat belt extension,” he says, his face beaming.

But what was wrong with him in the first place, to produce this level of unhappiness which manifested itself in over-eating? Personal issues? “Don’t go there,” he says again, and that gate clunks shut, just as the studio gates at Dumbarton did on his TV career.

Had the television career helped stave of depression?

“When I was playing Big Bob I was fine,” he agrees.

“When I reached the studio complex, a fake part of Glasgow surrounded by security, you become someone else for the day and that was ideal. Big Bob was happy. He wasn’t suffering from the depression. I was shut off from the rest of the world.”

Work gives a sense of purpose. Without work he ate more. But the rebooted Tom Urie is working again. Hard. He’s recently joined the CBBC series Molly and Mac. “I’m Colin The Chip Van Man. There’s a little irony in that.” He’s also featured heavily (no pun intended) in Oran Mor’s play season.

There’s another change in the life of Tom Urie. He now loves panto, which is just as well because he’s appearing in Glasgow’s Oran Mor summer panto this week, and at the end of the year he’ll be playing an Ugly in Dunfermline’s Gardyne Theatre.

“I’m the Mayor of Cumbernauld, who’s a baddie,” he says of the Glasgow stint.

“I wear a tartan suit identical to the one I wore in Tutti Frutti. (The 2007 stage show).

However, there was a time, he reveals, when he would rather have squeezed into Kylie’s hot pants than get up there on a stage for a panto run.

“The last one I did in Edinburgh was during the time my mother was ill. And I didn’t feel I was cut out of it. And on top of that I was always too heavy to get around the stage.”

Life is very different now. Now, he’s playing the Mayor of Cumbernauld, a rather camp character.

“It’s great fun,” he says.

Now, he combines acting with musical performance. Urie DJs in a Glasgow club and plays piano in a plush city restaurant.

So what is he? Actor or musician?

“I still don’t know what I want to do,” he admits.

But what’s inarguable he’s happy now. Not always balloon-light happy, but he can face most days. If he wakes up with “a bad head” he drives to Largs, takes the ferry to Millport and walks around it. “When I come back I feel amazing. It’s about changing your environment.”

He adds, smiling; “But I feel blessed to have the chance to walk again. I can get on a bike, where once it would have collapsed under men. How good is that?”

• Pure Freezin’, Oran Mor, Glasgow, until July 21.