AMY Macdonald was on stage in Germany, playing with her band and entertaining yet another appreciative audience, when she glanced at the front row.

“There was a group of girls who come to a lot of my gigs,” she says, laughing at the memory. “They made life-size paintings of not just me, but all of the band. As the show went on they didn’t just unveil them all at first, they did it bit by bit. So, we all had a life size painting of ourselves.

“It was amazing that they spent so much time doing that. We got them up on the stage and showed the whole crowd. To me that’s the crazy side. I always just try to write things that mean something and that move me. Almost all my songs have a story behind them and they’re all about a certain thing. People appreciate that. I don’t write songs about being on tour because it’s not what people can relate to.”

Macdonald is an engaging interviewee as she sits in Glasgow’s Malmaison hotel, a glass of sparkling water to hand. Her new album – Under Stars, her fourth since 2007 – is out this month. In March she embarks on a European tour that includes dates in Edinburgh, Inverness and Aberdeen. The latter two have already sold out. She’s sold more than nine million records worldwide since her acclaimed debut, This is the Life.

Under Stars marks a departure for the singer-songwriter. “I had never written songs with anybody in my life. I’ve got that typical musician thing where everything, 90% of the time, is suffering from crippling self-doubt. And 10% is being on stage.”

Though it has been almost a decade since This is the Life, she still finds it challenging opening up and writing with others.

“The thought of sitting with somebody and telling them my innermost thoughts and ideas was enough to bring me out in a cold sweat. It was something I’d never done but my bass player, Jimmy [Sims] is the exact same.”

To get over this, the pair decided to write the songs as though they were playing for Bruce Springsteen and the E Street Band so it did not feel so personal.

“As soon as we did that it made it so much easier and it made me relax. Within the next two hours we wrote the track Automatic, which is on the album. After that it just kind of clicked.”

Macdonald takes a lot of inspiration from her friends’ lives. The track Dream On, for example, is one she wrote for a close friend who was going through a rough patch.

“She got made redundant and her mum was unwell and everything seemed to be going to absolute rubbish for her”, she says. “It was awful and I was wishing there was something I could do. But then she got a job interview and that just changed her whole outlook and she was suddenly Mrs Positive.

“It was amazing and inspiring that she could have all this mess going on around her but this one tiny glimmer of hope brought her back. That inspired me to write Dream On. It sounds like a massive, positive, upbeat, happy song. But the verses are tinged with sadness and then chorus is the dreaming, live for the moment where she got her little bit of good news.

“It’s amazing because she’s in a great place now”, she adds. “Her mum is totally fine and she got the job and has been promoted a couple of times already. She loves the song. She tells everybody that’s her song."

While Macdonald has the rock-chick persona, sitting here in her black and red stripey top and black leather trousers, she has never felt the need to rebel and is very close to her family and friends. However, her mother does not share her petrolhead daughter's passion for fast cars. “She’s been telling me how I’m wasting my money and how I should sort myself out for the future but I’m just like, ‘bugger it, you only live once.’”

Although Scotland has some fabulous roads, Macdonald says the country's dreich days can be an issue. “The Scottish weather isn’t really conducive to a high-powered rear-wheeled drive car. I’d probably end up in a ditch,” she says, laughing, “But it’s great just being able to drive and getting a connection with a car. Getting the exhilaration and excitement of being lucky and able to drive on tracks and things like that. You can do what you want. It is an amazing feeling and buzz but also a great release as well.”

Cars seem to be the way the 29-year-old lets her hair down. Certainly, she has never felt the need to indulge in the celebrity lifestyle. “I’ve never been into the whole sex, drugs and rock 'n' roll. It’s not really me. We’ve been through so many economic downs and crises, people who are coming to shows have spent their hard-earned cash.

“If I’m out every night drinking and giving some half-assed show, I think it’s so disrespectful to the people who have worked hard so they can come and watch you.

“People tell me I’m not cool but I don’t care. To me these people are there to support me so I’m going to give something back. It means something to me to put some effort into the folk who have allowed me to do what I do.”

However uncool Finnieston's bearded hipsters may think she is, the singer has an impressive tattoo sleeve on her arm. Even with a fear of needles she has managed to cover herself in art work from love hearts to skulls.

“When you are somebody that’s creative it’s another way to get those juices flowing,” she says. “For me I always loved tattoos but I was terribly afraid of needles. When I was on holiday in Las Vegas with my friends, they wanted to mark the occasion and get matching tattoos.” She recalls waving about her arms in protest. “I was like ‘No, no, no. Not going to happen, not going to happen.’

“They had tattoos already, so they weren’t as worried as me. But then we decided to get something small to remember these few weeks, so we got these matching love hearts. It wasn’t painful at all and I couldn’t even give blood before. But it got me over my fear of needles so I decided I wanted a big crazy sleeve.

“I’ve always loved Alexander McQueen and the way that he has the icon skull. It’s made on these beautiful feminine silk scarves. It's two juxtapositions of this crazy scary skull on a lovely bit of silk. I always loved that and his designs. I wanted it to be rough, not girly. I wanted the skulls, and the roses and all of that.”

Macdonald is forthright on the subject of Brexit. “It’s been an extraordinary act of self-harm by the United Kingdom, and more so by England and Wales, to leave the European Union. I think it was really outrageous how the campaign was run, that people were lead to believe that all of the ills and problems in the UK were because of the EU.”

She has a strong following in Germany, Switzerland and other European countries. “I spend a lot of time in Europe. In the last week, I spent my time in Germany and the number one question I was being asked by journalists and radio stations was about Brexit.

“I was able to ask them what they thought about it and they’re baffled. There not sitting there saying they hate Britain, they’re wondering why Britain hates them. Over here, the press take the angle of two fingers to Europe. That’s not what’s going on in Germany and the rest of Europe. They are shocked.”

The young singer has been a strong advocate for independence in Scotland. In 2014 she performed at the pro-independence concert with Franz Ferdinand and Eddi Reader.

“People are saying they don’t want a second indy referendum, like Kezia Dugdale and Ruth Davidson. It’s OK to say that, but everything’s changed. The landscape has shifted massively – 2014 was under a completely different set of circumstances.”

This time last year, Macdonald was proposed to by her footballer boyfriend, Richard Foster, who plays for St Johnstone. She smiles warmly when talking about him and says she would be happy to marry him in denim and get hitched in Las Vegas.

“The nature of my job for this year means it’s pretty much a write-off. I can’t make plans because I’ll be touring and doing festivals. I don’t think I’ll be about that much but I’m not the kind of romantic, white wedding type. I would happily get married in my jeans.

“When I do get married it will just be close friends and family and we’ll go Las Vegas and do something fun. But it will be very last minute and very low-key.”

Macdonald is very clear that she is not a WAG and says the obsession with footballers' wives annoys her.

“I don’t meet someone and base them on the type of career that their partner has. It only seems to be because it’s football. If he did anything else nobody would be interested.

“It’s become a thing where the footballer is seen as not very bright with the typical blonde bimbo who doesn’t work. To me it’s laughable to put that into Scottish football. Maybe if you’re playing for Celtic, then fair enough. You’re earning fortunes but most people that play in Scotland earn a normal kind of wage.

“They are not turning up in gold-plated Rolls-Royces like they do in the English premier league. It’s people working hard in a very short career.”

Despite earning over £4 million last year, Macdonald still lives in Scotland. Moving to London or America is not something she has even thought about.

“So many people think that now I’ve done well I should go and live in London or LA. It’s just not me. I’m happy here. I’ve got my family and friends and Scotland is such a beautiful country. I love living here and having everything on my doorstep.

“I’m not a part of that celebrity bubble. If someone was to say to me right now, do I want to go hang out at the Golden Globes or do I want to go out with friends on Sauchiehall Street I’d be with my friends.

“I wouldn’t feel comfortable with all the glitz and glamour. I’m happy being chilled out and quiet, it works well here. There isn’t the crazy paparazzi and reality TV bubble that exists everywhere else. We feel normal up here.”

Under Stars is released on February 17. She plays Edinburgh’s Usher Hall on April 5; Ironworks, Inverness, on April 12 and Aberdeen’s Beach Ballroom on April 13.