Interview: Katie Melua talks ahead of Birmingham Symphony Hall show

Her demeanour is different from that of other rock stars. Katie Melua knows she doesn't need to get into a game of interviewer-chess. She's not a performing seal. She doesn't need to balance a metaphorical ball on the end of her nose and bark.

Katie has a confidence and self-assuredness that others might lack. Having secured a dozen platinum discs in the UK and many more around the world – two number one albums and four more that hit the top 10 – she has amassed a fortune estimated at between £12 and £18 million. Not to mention her album, Call Off The Search, which is one of the UK's top 100 best-selling albums of all time.

An audience with Katie Melua is an audience with a bona fide star. The Georgian-British singer/songwriter – who is also an actor, model and world record holder for playing the deepest underwater concert 303 metres below sea level – is a class apart.

She doesn't dance to anyone else's tune – not, even, to the tune of the svengali who made her.

Before signing Katie to his Dramatico label, Mike Batt was best known for creating The Wombles and writing the Art Garfunkel chart-topper Bright Eyes. And then he discovered Katie and guided her career while also working with Carla Bruni, Marianne Faithfull, Caro Emerald, Gurrumul and others.

He found his protégé in 2002 and wrote six songs on Katie's Call Off The Search album, including The Closest Thing To Crazy. The record sold 1.8 million copies in the UK and three million overall, making Katie the biggest selling female artist of 2004. The follow up, Piece By Piece, which included the Mike-penned hit Nine Million Bicycles, sold even more as it became an international hit.

But in 2014, at the end of a 10-year contract, Katie said goodbye. Mike wanted to spend more time with The Wombles – and no, that's not a joke, he bought the TV, film and music rights so that he could turn it into a film. Katie decided it was time to move on. And while Mike is hanging out with the residents of Wimbledon Common, Katie is also focusing on matters closer to her heart – namely a Christmas album with a Georgian, all-woman choir.

The result of her two-year project is In Winter, her seventh album. She'll play songs from that, as well as her greatest hits, when she headlines Birmingham's Symphony Hall on December 1.

"It started about three years ago, in the middle of 2014. I was working on another project that was based in Georgia. I'd made six records with Mike Batt and after that we parted ways. Our goals had started to shift over those last few years," she says.

They had. Katie, ever the diplomat, has described their parting as being mutual: "Maybe more mutual on one side than the other. I think it has been mutual, um, eventually."

It freed her to fly out to Georgia to begin an esoteric project that, one imagines, would never have made it past the taste police at Dramatico. Katie acknowledges the debt she owes to Mike and the helpful way he developed her career and she says the thought of working without him was daunting.

"I didn't know what I would do when it came to making a record without Mike. Then I came across the Gori Women's Choir, in Georgia, while I was working on a dance project. Things didn't take off with the dance project but I was fascinated by the Gori Choir. I met them where they rehearsed, which is out in the mountains. They rehearse every day and are sponsored by the local townsmen.

"It's hugely important to them, three members have been doing it for 30 years. They used to tour but with the collapse of the Soviet Union it meant they had to halt that. I was blown away by them. I'd never heard so many voices sound as one, like one creature. They blended so well together. There was so much power and precision and it was like hearing the most perfect woodwind orchestra."

Katie enjoyed listening to the Gori Choir sing in their native language. It was more guttural than English.

"They use a certain part of their throats when they speak. It is more guttural and less forward-in-the-mouth. It was this weird mix of the language," she notes.

Katie came away from the meeting inspired. She knew that she wanted to work with them but wasn't sure how that might be possible. Winter 2014 came and went and she decided she ought to make a festive record.

"I really wanted to make a certain type of record, something that I don't feel is made any more. I wanted to do something that had the warmth of a Frank Sinatra or Johnny Cash Christmas album, but that dealt with Christmas in a modern way.

"I felt that if I was going to do a Christmas record I would have to talk about Christmas shopping, for instance, and do that in a grown-up way, not a comic way. I started thinking about what I would want to hear in December when it's too cold to go outside and the fire is going inside. For a lot of people, that's the only time they get to slow down. In my case, living in London and having a mad career, that's certainly true."

So, as winter 2014 rolled into 2015, Katie decided she should join forces with the Gori Women's Choir. She went back to Georgia to sing a few Christmas carols and see whether her voice and their voices would blend together.

She enlisted the help of renowned British choral composer and conductor Bob Chilcott, who has worked with the King's College, Cambridge, and many, many others.

"That solidified it. He's based in Oxford and has worked with everyone. Once he was on board, I decided to make it. I wrote to Bob about my ideas and he replied and seemed interested."

So Katie returned to Georgia to record four tracks. It was too expensive to fly the Gori Choir to the UK – indeed, it was too expensive to fly them to the Georgian capital of Tbilisi. Katie and Bob had to go to them.

"We shipped 12 boxes of musical equipment to Gori so that we could record them. We had to go to them and take every little thing. I don't think I could have convinced a producer to join us because it was so basic, so we just went."

Katie wanted to record with acoustic guitar, her vocals and accompaniment from the choir. By October 2015, she'd recorded the first four tracks and the project was alive. "It was an experience. It was good."

She returned to the UK and listened to it afresh, to make sure the enthusiasm she'd felt while in Georgia wasn't misplaced. To her relief, it sounded just as good back in England. The project went against the grain of conventional thinking.

"As far back as 2014, I had a conversation with my agent about how long it would take. He's one of the biggest music artist agents and he said he needed an album out in early 2016. I told him there was no chance. I said he wouldn't get anything from me until 2017 or 2018 at the earliest."

The Gori Choir meant Katie's programme moved forward a little. But she's aware of how wilful she can be, how much she defies conventional wisdom.

"I don't feel the music industry is structured to allow a fast turnaround of great music. I don't feel you can work at the pace the industry wants you to work with," she states.

And so she works at her own pace, unwilling to make the compromises that would be required to do things more quickly.

Working without Mike has been an eye-opener. Though she was keen to move on, she didn't realise how much she depended on him until he was no longer there.

"That's been a big difference because this is my first record without Mike. Until we parted ways, I didn't realise how much of the creative responsibility he had on his shoulders. That kept the burden off my shoulders, certainly in my twenties. So it took a while to learn those lessons. To do anything good takes time and research and experimentation. You've got to be able to fail and learn from it. There's been a lot happening behind the scenes that I've cherished and found fascinating."

It's led her to where she is today. She still gets on with Mike. The two catch up to talk and converse about past work. "It's funny because I saw him recently and we were reminiscing about the first ten years and marvelling at what happened.

"I literally came out of school and went into it. I was doing the second year of my A-levels and making Call Off The Search. It came out the year after and then my life changed completely. Mike formed his own label around it. It was really remarkable.

"I have to say the break-up, if you can call it that, was complicated and difficult. But we said to ourselves that no matter what happened when we were separating, everything we achieved would be remembered above the complication.

"I think the biggest thing was the fact that Mike held the responsibility of creatively making the work. He was in charge of it. Even at the time I didn't realise the difficulty of it. To be the decision-maker is a lot tougher than you think it's going to be."

Katie has always stood apart from her contemporaries. She's avoided the cheap and demeaning; she's as likely to enter the Big Brother house, feature in Chat magazine or fly out to the Jungle as a polar bear would.

"I'm glad that as a management team, they never forced me in a particular direction. The profile was always about the music rather than different types of fame. It was great. There were points where we got stuck and we didn't always agree on things but overall it was a great thing for someone being in their twenties and moving through the industry with an experienced hand."

Katie hopes In Winter strikes a chord as we head towards Christmas. But she's proud of the work, whether it's successful or not.

"What I care about is whether the work is great. I'm not interested in whether it's my creative idea or vision. In the West, it's all about the story of one person. But in Georgia, it's a less individualistic culture. That mindset is contagious and when you're part of a team, it means there is less pressure on yourself. It's a less egotistical environment and you end up making better work because you gather a good team," she says passionately.

Katie is looking forward to returning to Birmingham's Symphony hall, where she'll be accompanied by the Gori Choir. "Some of them have never been to the UK or even left Georgia before. So securing a tour with their involvement has been a pleasant surprise. The album is only 10 songs, so we'll go beyond that with a trio doing some of the songs that people know and love."

And when it's all over, she'll retreat to London for her own family Christmas with husband, World Superbike racer James Toseland, who she married at the Royal Botanical Gardens, in London, in 2012.

"That's the thing. I really work hard to make as much time as possible for me and James, as well as my family back in Georgia. What's amazing about the incredible husband that I married is that he really understands what it's like to have a job you're obsessed with. He is incredibly supportive. If things get a bit mad at work, he's incredibly understanding."

With a new career, a loving husband and a bright future, Katie's next project is simple – she just wants a Happy Christmas.

Katie Melua, Birmingham Symphony Hall, Thursday, December 1, 7pm. Tickets cost from £25. Visit www.thsh.co.uk or call 0121 780 3333.

By Andy Richardson