Last week, Kathleen McDermott heard the director shout "cut" on the final scenes of her debut movie. Then, in London, she cut a deal with a prestigious showbiz agency to further her acting career.

Yesterday, she was back in Springburn, Glasgow, cutting hair in Milano's barber shop.

The story of how a trainee barber ended up with a plum role in the film Morvern Callar is itself straight out of the movies.

Kathleen was walking along Argyle Street in Glasgow when the film's casting director handed her a note inviting her to audition for the part of Lana from Alan Warner's cult novel about two Oban shop assistants on the rampage in Spain.

Not being a shy or retiring type, she went for it and, after auditions with director Lynne Ramsay, of Ratcatcher fame, she was given the role.

She didn't know it at the time but Kathleen, with no acting experience, had beaten 3000 others, including hundreds of established actresses, for the part.

With eight weeks off granted by her bosses Gerry and Paul at Milano's barber shop in Vulcan Street, she set about becoming a film actress.

Kathleen explains in her un-affected, natural Glasgow accent that she managed to remain "dead calm" through the entire shoot in Glasgow, Oban, and Almeria in Spain. Except, that is, for fits of giggles which made her queen of the out-takes.

"Lynne, the director, didn't let me read the script, so all I had to do each night was learn my lines for the next day.

"I hadn't read the book either so I could just concentrate on dealing with each day's shoot as it came," she said. "I wasn't allowed to see the rushes either."

But there was no shortage of colleagues on the film unit telling Kathleen: "I've just seen the rushes and you are brilliant."

Such praise might easily turn the head of a young girl, but 23-year-old Kathleen says: "I've got a very long way to go before I become a luvvie."

She added: "Some days, when we would get to the sixth or seventh take of a scene, I would begin to worry I was doing it wrong but the crew were great in pointing out that it was usually some technical problem and not my fault."

Samantha Morton, the Bafta-winning rising star who plays the eponymous heroine, was also tremendously supportive, said Kathleen.

"Sam is a very strong person and I thought I might be quite intimidated playing opposite her, but she couldn't have been more helpful."

Their friendship will be renewed shortly when Kathleen visits Ms Morton in Los Angeles where she is filming Minority Report with Steven Spielberg.

During the filming, Kathleen received a number of offers from Scottish and London agents.

She has signed up with Conway-Gelder agency who also represent Samantha Morton and Anna Friel.

"I know how lucky I have been with Lynne Ramsay and casting director Des Hamilton. They've been so patient and taken time to get me through this first film.

"They let me be myself, with my own accent, although I had to speak a lot slower and a more polite. Lynne let me change bits of the scripts to the way I would normally speak.

"Any future roles in film or on TV will be harder and I will have a lot to learn."

Kathleen's eyes may be on the stars but she is trying hard to keep her feet on the ground.

"I have eight weeks left of my barber's course to do at the College of Commerce and I hope to finish it. If I don't make it in my new career, I can always go back to cutting hair."

She confesses that the hardest part now is waiting to see the finished version of Morvern Callar in the cinema.

"It could be next year before it comes out. I'm desperate for the premiere.

"I hope it's in Scotland so I can take my mum and dad, my aunties, and all my pals."

If Kathleen succeeds in establishing an acting career, she admits it might just be a springboard to a more important ambition. She would like to be a successful singer.

Like many a Glasgow girl, she is to the karaoke born. She spent two years in Tenerife in a cabaret show and still pursues her hobby as occasional chanteuse at the Shanghai Shuffle Chinese restaurant in Bath Street, Glasgow.

Boss Gerry, speaking of his apprentice barber who may soon have trimmed her last customer, said: "We'll all miss her. She fairly brightens the place up."