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 in actor Tom Urie who has grown out of, in reverse fashion, his River City character.

Urie, 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.”

Urie 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. “The flight attendants wave them in the air as they bring them to you. And they are always bright orange. But no more.

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? Did becoming another character help? “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 in 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. What? Come on Tom, how can anyone hate panto? It’s the best fun you can have without alcohol.

“I’d banned myself from doing panto,” he recalls. “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. It wasn’t a comedy role. And on top of that I was always too heavy to get around the stage.

“But then producer Robert C Kelly offered me panto in Dunfermline, playing the Dame, and I loved it.” He adds, smiling; “I even did dance routines.” Will he love playing an Ugly? “Oh aye,” he says, smiling. “Bloke in a dress is always really funny.”

If Urie was lost without his River City character to hide behind, does this suggest he needs to be an actor?

“I didn’t think I had a need to be an actor,” he wonders. “Growing up in Paisley (“next door to Gerard Butler - haven’t seen him since”) I loved paying Star Wars and make-believe and pretending. And I loved the children’s book The Swish of the Curtain, about kids who put on plays. But I didn’t think I could ever have become an actor. I figured ‘No one from Paisley becomes an actor.’

What about his then next-door-neighbour, Gerard Butler?’ Oh, hang on a minute. He grins. “My mother suggested am-dram, but that never happened.”

Urie’s big sister bought him a guitar when he was four. Music took over and at Paisley Grammar he’d teach himself piano at lunch times.

After a stint on the dole, Urie attended Perth Rock Music College. “It was a hoot. It was like Fame but everybody smoked. The exams were in the pub.”

Then opportunity knocked. “When I went to work with Chewin’ The Fat I only got in because I was Karen Dunbar’s pal. Then it all sort of grew. And the Comedy Unit became my agents.

Now, he combines acting with musical performance. Urie DJs in a Glasgow club Tropicana on Saturdays and plays piano in a plush city restaurant. He’s appearing at the Glamis Prom in August. And there’s the Movies to Musicals showcase with Glasgow Philharmonia.

He appeared in the Proms in the Park last year. “Musical bunjee jumping,” he says, smiling. “Four days rehearsal and I had to get up and sing Nessun Dorma. I felt such a fraud. But Janey Godley (the comedienne) helped. She took me to Slater’s and bought me a nice suit. It was like going shopping with my mother. She bossed all the assistants around. But it all worked out. I hit the note for Nessun, jumped off stage and into a t-shirt to go and do a DJ stint.”

So what is he? Actor or musician? “I still don’t know what I want to do,” he admits. He also reveals he doesn’t actually go to theatre. “Only if my pals are in a play. But not really. I’m more into going to gigs.”

Urie reveals he was a little bit of a loner as a kid. An outsider. He doesn’t talk about his personal life except to say, when pushed, he’s single. There’s a sense he’s still on the margins.

“Yes, that’s true,” he acknowledges.

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.