It’s a bona-fide Boston holiday tradition that, 10 years along, has now captured wintertime fancies in other parts of New England.

This month, “A Christmas Celtic Sojourn” celebrates its first decade of bringing to the stage an inimitable blend of Celtic music, song, dance, and storytelling, with a series of performances from December 15-22 at venues in Worcester, Providence, Rockport, and Derry, NH, as well as the Cutler Majestic Theater in Boston.

True to form, this year’s show includes a combination of frequent “Sojourn” participants (pioneering Irish band Solas, a cappella harmony quartet Navan, the Harney Academy of Irish Dance), more recently appearing acts (the fiddle-harp duo Chris Stout and Catriona McKay and cellist Natalie Haas) and highly anticipated debuts, with Scottish singer Alyth McCormack and innovative dancers Cara Butler and brothers Jon and Nathan Pilatzke. Also present will be bassist Chico Huff and percussionist Ben Wittman, long-time contributors to the show.

And, as always, “Christmas Celtic Sojourn” will be lovingly hosted and guided by its creator, Brian O’Donovan, who, while hoping the show might catch on back when it premiered at Somerville Theater in 2003, honestly didn’t expect it to do so on this kind of scale.

“I certainly felt, at the beginning, that we could put together a production that people would enjoy as an evocation of what we all love about the Christmas holiday season: shared family memories, the warmth of friends, music to lift the spirit,” says O’Donovan, the host of WGBH-FM’s “A Celtic Sojourn,” which provided a basis for the show. “But I really thought it would be more of a church-sized affair, one performance with maybe a few hundred people in the audience. Instead, we kept adding shows, and then we started taking the show on tour to different cities in the region, and it hits you, ‘Something is really going on here.’

“Now, we’re working a good deal of the year on ‘Christmas Celtic Sojourn,’ and it’s gotten pretty elaborate in terms of costumes, staging and other aspects, and you wonder, ‘Is it too much work?’” says O’Donovan, whose wife Lindsay will also be part of the show. “But the experience is still an uplifting one, and no matter how ambitious we might get, the show still has that very homey, folksy quality to it. That’s a big reason why people keep coming out to see it – along with the fact that we have some remarkably talented individuals and groups involved in it.”

McCormack will join a long line of renowned Celtic female vocalists – including Cara Dillon, Karan Casey and Karine Polwart – who have entered the “Christmas Celtic Sojourn” spotlight. A native of the Isle of Lewis (off the northwest coast of Scotland) who is now living in Dublin, McCormack has appeared on some two-dozen albums and has two solo recordings to her credit, a body of work that covers a variety of music, from Celtic and folk to jazz, classical and indie. Her resume also includes appearances with The Chieftains, including a particularly memorable one in Boston that clinched her invitation to perform in “Christmas Celtic Sojourn.”

“I’ve loved Alyth’s voice for years; she was someone we had in mind for the show a long time,” explains O’Donovan. “Earlier this year, Alyth and The Chieftains, along with the band The Low Anthem, did a studio presentation at WGBH and it was riveting. So we made sure to put her on the roster for the show this time around.”

Another asset for McCormack is her extensive acting experience, on both stage and screen, notes O’Donovan. “There is an element of theatricality in ‘Christmas Celtic Sojourn,’ so Alyth fits in very well in that regard.”

This year’s other newcomers, the Pilatzke brothers and Butler, also have worked with The Chieftains, and thus will likely be familiar to some in the audience. The Pilatzkes are steeped in the “high-off-the-floor” Ottawa Valley style of stepdance, while Butler is an award-winning Irish stepdancer who appeared in “Dancing on Dangerous Ground” during its 1999 run in London’s West End (she also starred in the Folger’s Coffee “Dancer’s Morning” TV commercial). The three are members of The Step Crew, a new production that blends the Ottawa Valley and Irish dance traditions with modern tap.

“We’re very excited to have Jon, Nathan, and Cara here,” says O’Donovan. “The fact they’ve worked together, and with Alyth, as part of The Chieftains’ tours, is a big plus.”

Navan, known for spellbinding close-harmony singing of material from Scotland, Ireland, Wales, Brittany, Cornwall, and the Isle of Man, among other places, makes its return to “Christmas Celtic Sojourn” as a quartet instead of a trio.

“They were in the very first show, and back then they were a quartet,” says O’Donovan. “It’s definitely very special to have them here with us again as a foursome.”

O’Donovan is also abundantly pleased to have Stout and McKay back. The pair electrified the audience two years ago with their intricate pas-de-deux of Scottish harp and Shetland fiddle, drawn from tradition but incorporating modern influences to create exciting, elegant sounds that seem drawn from the very geography of Scotland and the Shetland Islands.

“Chris and Catriona stole the show in 2010,” O’Donovan declares. “In many ways, they’re one of our most iconic acts, in the way they combine the old and the new.”

Equally iconic is Solas, of course, which has carved out its own unique position in the Irish music spectrum, squarely at the intersection of tradition and modern, and with virtuosic musicianship to boot. Their most recent album project, “Shamrock City,” further affirms their reputation as one of the most eminent Irish groups of the past couple of decades. The project is the creation of band leader Seamus Egan, who also is the “Christmas Celtic Sojourn” musical director, and was inspired by the experiences of his great-great uncle, who immigrated from Ireland at the turn of the century to Butte, Montana, an unlikely but robust Irish outpost.

“We are in fact going to be incorporating an outgrowth of the ‘Shamrock City’ project into this year’s show,” O’Donovan says. “In his research, Seamus came across the story of ‘The Joshers,’ a Butte tradition in which, following the Christmas Eve festivities, people would go around leaving gifts, food or money on the doorsteps of those in need. This was a tradition that continued right up until the 1970s.

“Seamus is a big part of the reason why ‘Christmas Celtic Sojourn’ has been so successful,” adds O’Donovan. “Year in and year out, he does a phenomenal job arranging the music. Besides the full ensemble numbers, there are opportunities for some special collaborations: You might see, for example, Winifred Horan from Solas pairing up with Natalie Haas, who has almost single-handedly made the cello a ‘Celtic instrument,’ as well as with Chico and Ben.

“And when it comes to great work, the same holds true for Paula Plum, our artistic director. There’s no question as to how valuable they’ve been to this show.”

This year, O’Donovan notes, will see more emphasis on vocal performances. “We’re always trying to utilize that characteristic of the show to a greater degree. We not only have Navan and Alyth, but some great vocal talents in Mick McAuley and Eamon McElholm of Solas, as well as Lindsay, so that will definitely be a highlight.”

Running an annual production for a decade, O’Donovan says, means striking a balance between retaining aspects that audiences like and implementing changes to prevent staleness.

“It’s become a tradition for the lead female singer in the show to lead ‘O Holy Night’ – given the quality of singers we’ve had, that’s a no-brainer,” he says. “Another tradition is the young Harney Academy kids closing out the first act with their high-energy set dance. For a while, we would say, ‘Well, we’ll change that next year,’ but it is the cutest, most wonderful thing to see, and the audience absolutely loves it. So there’s really no inclination for us to take it out.”

Over the course of its first decade, “Christmas Celtic Sojourn” has benefited from the infusion of talents and skills from many people, O’Donovan says, whether they have been out on the stage or behind the scenes. He cites, for example, Kieran Jordan and Kevin Doyle, who “have done so much for the dance choreography and performances.” Even though the roster may change somewhat from year to year, the imprint of various individuals on the show remains.

“Ultimately, ‘Christmas Celtic Sojourn’ integrates a lot of people’s visions, yet at the same time there’s a unity to the show. It’s kind of like a family’s Christmas ornaments: They may be made of different materials, and some may be older than others, but when you put them all on a tree it looks like Christmas.”

For ticket and performance information on “Christmas Celtic Sojourn,” see wgbh.org/celtic