The Utah Symphony's holiday concert tradition takes a soulful turn Dec. 19 and 20. Instead of the usual concert built around Christmas-themed works by classical composers, the orchestra is featuring a type of music whose name is synonymous with "glad tidings" -- gospel, that is.

Audience members can expect a moving experience as they experience Christmas music drawing upon the traditions of African-American spirituals, blues and gospel music. Headlining the event is gospel singer Renese King, of Boston, whose bravura performance at the orchestra's 2007 Deer Valley Music Festival planted the seeds for this week's events.

King's invitation to solo on a Utah Symphony patriotic program at Deer Valley came after her performance of Christmas spirituals during a Boston Pops holiday concert impressed Keith Lockhart, music director of both groups. Once at Deer Valley, King not only thrilled the audience with her heartfelt singing, but won the admiration of Utah Symphony administrators, too.

"I fell in love with her voice," said Jeff Bram, vice president of artistic operations for the Utah Symphony. "She's one of those performers who sort of stops time when she's singing."

Utah Symphony chorus master Susanne Sheston was similarly affected. "I remember being moved to tears by the beauty of her artistry," Sheston said. "She's a perfect choice for the holiday concerts. We'll have favorite carols and well-known Christmas tunes, but with a gospel-spiritual flavor. I think it's wonderful."

Assistant conductor David Cho will conduct this weekend's performances, which also feature the orchestra playing Ralph Vaughan Williams' "Fantasia on Greensleeves" and selections from Bizet's L'Arlesienne Suite and Tchaikovsky's Nutcracker Suite.

A classically-trained tympanist, King knows her classical concert etiquette well: Stay in your seat, and don't clap until the piece is over.

That's in contrast to the communal feeling of African-American churches when spirituals such as "Go Tell it on the Mountain" are performed, calling for hand-calling, shouting and singing along, with plenty of stomping and swaying from the audience.

"You're completely at the opposite end of the spectrum with gospel music," she said with a laugh. "This is very much about participation. If people feel like getting up and shouting, or singing along, they will. But some people experience music best if they keep their eyes closed and take it in, while some experience it in a more participatory way. Really, it's all good."

Gospel music originated as a way of "helping people get through difficult circumstances," King said, adding that it carries a spirit that resonates with the experiences of its listeners. "Whether the piece is meditative or lighter, it comes from a place that's about your own experiences infusing the music."

King put her belief in gospel music's uplifting power into practice after the deaths of six coal Utah coal miners and three rescuers in 2007. Along with members of the Utah Symphony, she donated her talents to give a free concert for grieving communities in Carbon and Emery counties. "It was a powerful thing to be involved in, and an honor for me," King said.

King's Christmas selections range from the blues-tinged "When Love Came Down," to the contemplative tune "Who Would Imagine a King?" (from the film "The Preacher's Wife"); to a soaring gospel-flavored riff on "The Little Drummer Boy." As a percussionist, King has particular affinity for that one. "It's mesmerizing to see someone really go to town on the drums," she said.

Members of the Utah Symphony Chorus will veer from the strait-laced boundaries of their usual choral-orchestral repertoire to back up several of King's selections. "This concert is a fun change of pace for the symphony chorus," Sheston said. "It's definitely a stretch for them . . . but many of these singers have church choir backgrounds, and a lot of us enjoy singing along with favorite pop songs in the car. This gives us a chance to flex performance muscles we don't use during the regular season."

Sheston said the symphony chorus has practiced swaying and clapping in anticipation of King's arrival, and says it's a "fair bet" that King will find more ways to loosen up the group when she arrives this week. "Renese is also a choral conductor," Sheston said, "and I'm expecting that she may have a few pointers for our choir."

Catching the spirit of King's music won't be difficult, Sheston said, because of the irresistible pull exerted by gospel music. "It's contagious, and has a great sweeping spirit. It sweeps you up."