Before Mairead Carlin was a member of Celtic Woman, she was one of the group’s biggest fans. The young singer from Derry in northern Ireland admired the all-female ensemble’s honest approach to music, and she listened to their albums when she wanted to feel uplifted. As coincidence would have it, it was during one of those times – a difficult period in her life when she’d just been dropped by a record label and was making the rent giving voice lessons to children – when she got the call from the group’s producers, asking if she might be interested in joining Celtic Woman for their next tour.

“I just couldn’t believe it,” Carlin told me in a recent phone interview. “It was an amazing opportunity and I was so grateful for the chance. I’m still so grateful. Quite honestly, I don’t know where I’d be without Celtic Woman.”

When I reached Carlin in her hotel room, she and her mates – Susan McFadden, Eabha McMahon and Tara McNeill – had just arrived in Santa Rosa, California in preparation for their first performance in the U.S. since March 2015’s 10th anniversary tour. They were getting ready to launch their Home for Christmas: The Symphony Tour, which will bring them to Wabash’s Honywell Center Thursday, December 16, and Carlin was fresh from a talk with her fellow Celtic women about their individual journeys as youthful singers to professional performers.

Carlin grew up in a musical family. Her father was a band leader who often traveled America, Canada and Turkey, entertaining troops at naval bases, her sister a classical violinist, and her grandmother a singer, and music formed the backdrop of her childhood. She began singing lessons at age four, but her teacher refused to subject Carlin to a strict regimen of technical instruction, and Carlin credits the freedom she had as a youngster to find her own voice, along with her triumphant turn at BBC Talents Young Singer Competition at aged 16, with helping shape the singer she is today.

“The girls and I were talking about how, if you get too technical with young singers, it can be a real hindrance,” Carlin said. “Singing is such a primal thing to do. When a baby cries, it’s almost like they’re singing. We all start out singing, and if someone tells us how to do it when we’re too young, it can take the joy and uniqueness out of it. It should be fun, it should be free. I’m just glad my teacher let me do that.”

Carlin, whose resume includes a world tour with her friend and mentor Don McLean, jumped at the chance to join Celtic Woman in 2013 because she sensed that it, too, would give her the freedom to be herself and perform music that is important to her on a personal and cultural level.

“Each one of us takes the music incredibly seriously,” she said. “Eabha, for instance, is dedicated to keeping the nearly lost art of sean nos, a traditional Irish way of singing, alive. It’s her mission, and I really admire that. Susan, when she goes through a song, makes sure she understands every single word of it and the emotion behind it, and she works hard to communicate that to the audience. The same is true of Tara. Every note is clearly thought out; every moment is a chance to communicate through music, and it’s really a privilege to be part of a group whose music comes from such a heartfelt place.”

Celtic Woman first formed in 2004 when artistic partners David Kavanaugh, Sharon Browne and David Downes – the musical director behind the smash hit show Riverdance – decided to pool their energies into recruiting five Irish women vocalists who would then tour Europe and the U.S., performing both traditional Irish ballads and modern music with a Celtic twist.

A year later, PBS aired Celtic Woman’s sold-out performance at Dublin’s The Helix, and the group’s eponymous debut soared to the top of the Billboard World Music charts. Celtic Woman became, in short order, a favorite act stateside.

The group has gone through a number of lineup changes in its 12-year history, but one thing has remained constant: Celtic Woman’s absolute devotion to the music they perform, be that music lifted directly from the traditional Irish songbook or something a little more contemporary, like Celine Dion’s “My Heart Will Go On,” which appears on Celtic Woman’s newest album, Voices of Angels.

Another thing fans can count on? The members of the group getting along like the proverbial peas and carrots. Their gruelling eight-months-on-the-road touring schedule would be impossible otherwise.

“Being on the road so often means we can’t just go home and close the door,” Carlin said. “We sleep on the bus together, we wake up together, we share a stage together. The truth is, we get on great. Eabha was my bridesmaid at my wedding. That shows, I think, how much love we have for each other. Obviously you have to have musical talent to be chosen for Celtic Woman, but the producers give a lot of thought to personality as well. Everyone in the group has a lovely disposition. It just wouldn’t work if our egos got in the way.”

Celtic Woman are known not only for their lack of backstage drama but their ability to take a Christmas classic like “Silent Night” and make it new again for every listener. This year’s holiday-themed show, according to Carlin, has the potential to delight even the most jaded Scrooge in the house. That’s because the orchestral arrangements – or, in some cases, lack thereof – are designed to surprise, all the while staying true to a tune’s original appeal.

“There’s a real mix in the repertoire,” she said. “There are traditional Christmas songs and really fun numbers like ‘Santa Claus Coming to Town,’ and ‘Joy to the World’ and quieter ones like ‘It Came Upon a Midnight Clear.’ There’s really something for everyone, and our hope is that the audience has as much fun as we do. This is our favorite time of year. This is when we feel most at home, and the goal is for everyone to link onto their loved ones and have a nice night.”