When people see me on television or acting on film with Samantha Morton in Morvern Callar, they ask why I still sing karaoke three nights a week at the Shanghai Shuffle on Glasgow’s Bath Street. The answer is that it’s both a hobby and a job to me. I like doing it, so why should I stop? I’m still a normal person and I like doing normal things.

I came across karaoke by accident. I was 17. I’d fallen out with my boyfriend and was sitting in the house, all down in the dumps. My mum and dad were going out, so I was going to be left alone. My mum suggested I should come with her to the karaoke where she likes to get up and sing. I was like, “Naw, I’m not going out with my mum.”

But we went and during the evening I was coming out of the lavatory when the guy called out, “Kathleen McDermott”. My mum has the same name as me, so I assumed he meant her, but she said he meant me. She’d put me up to sing Karen Carpenter. I was so embarrassed.

The very first song I sang was Top of the World. I didn’t feel top of the world at the end of it — I was a nervous wreck.

The next week I went down again and it was a different karaoke guy. I didn’t want to sing in front of a new person — I was so nervous about singing again — but I did. I sang that same song for ages and eventually started branching out with others.

Now I’ve been doing it for 13 years and I sing anything and everything. We’ll be doing 12-hour shifts at the Shanghai Shuffle in the run-up to Christmas — my voice is going to start sounding like Macy Gray’s.

My first pub engagement was at the Tower Bar on a Saturday night. I’d come third in a competition where I’d been up against comperes and professional singers and, as a result, I’d been invited to do a set. I wasn’t shy about singing.

But it was an excellent night, everyone was on their chairs. The boss came in and said: “Kathleen, I’ve never seen the pub like this in my life. It’s absolutely jumping.”

The memory of my initial nervousness helps me empathise with people coming up for the first time. I tell them everybody is in the same boat and karaoke isn’t about serious singing. I always encourage the worst singer of the night to get up. It makes everyone feel comfortable.

The most popular karaoke songs are I Will Survive by Gloria Gaynor and Angels by Robbie Williams. They’re quite difficult, but that’s the whole thing about karaoke — it’s a laugh.

Personally I like to sing Left Outside Alone by Anastasia — I love the way she goes deep at the beginning, then really high halfway through — and Don’t Stop Me Now by Queen, because I was brought up with it.

I do get people coming just to see me. Last night a guy came up and said: “Were you in Morvern Callar?” I said: “Aye” and he said: “Oh my God, this is such a big experience for me to meet you.” I had to do a duet with him, so he could tell his pals he’d sung with me.

I love the atmosphere of the Shanghai Shuffle — there isn’t anywhere else where you’d feel odd if you weren’t jumping about and having a laugh. A lot of people would love a job like mine.

I liked it enough to work abroad for two years, singing in cabaret. I’d been on holiday in Tenerife for a week and thought I’d really like to work there.

I saved up for six weeks and got a one-way ticket. I didn’t have anywhere to stay or a job — I just went into some karaoke pub, sang a few songs and the woman offered me a job.

She then sold the pub to do cab-aret with me. It was a French and Saunders-type thing called Sisters of Doom. We dressed up as nuns for two years and went round all the pubs doing two 45-minute shows a night. I loved it. When I left they got me champagne and roses.

My biggest ambition is to have a number one film, a number one album and a number one single all at the same time. How good would that be? I’ve just finished filming Nina’s Heavenly Delights, a Bollywood romantic comedy, a bit like East Is East. The actors all came down to Shanghai Shuffle for a night — me, Art Malik from Holby City and Raji James from EastEnders, all having a laugh.

I’m due to be shooting the Burns film in the spring with Brian Cox and Gerard Butler. I’m playing Jenny Clow, who falls pregnant to Rabbie Burns.

It’s very easy to be carried away when you go to big events and meet the stars. I still get star-struck. I go into the lavatory and phone my sister and go: “You’ll never guess who I was talking to tonight.”

I was discovered by an agent when I was shopping in Argyle Street. And there are probably lots of people out there who could do what I’ve done. My life changed completely because of Morvern Callar, but if it hadn’t happened I’d probably be in the Shanghai Shuffle as always.

A former hairdresser from Glasgow, Kathleen McDermott, 30, made her acting debut in Morvern Callar. She won a British Independent Film award for best newcomer for her role as Lanna and went on to make two small budget films, Out of the Cold and Milk

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