As he set a Dickensian dinner table in a Guthrie Theater rehearsal room, 13-year-old T.J. McCormick was rocking some unusual footwear with his shiny techno-fabric basketball shorts — old-fashioned black lace-up ankle boots.

Not his everyday choice of kicks, but he had to get used to wearing them. Beginning this week, he’s playing dutiful son Peter Cratchit more than 50 times over in “A Christmas Carol.” This in addition to attending Highland Catholic School in St. Paul full-time and the homework that comes along with it.

“Line!” he calls out, having momentarily forgotten what he’s supposed to say about the gravy. Then he carries on, like the pro he seems to be, as at ease as the adults surrounding him despite his far fewer years on stage.

McCormick is one of four Twin Cities child actors appearing as a Cratchit kid this season. The others are 12-year-olds Delaney Hunter (Martha Cratchit) and Caitlyn Carroll (Belinda Cratchit) and 10-year-old Otto Dregni (Tiny Tim). McCormick cut his thespian teeth in productions at such smaller theaters as Children’s and SteppingStone, but this is his first gig at the Big Blue, the top of the line, the Guthrie. For the next six weeks, the four are the chosen Kids of Christmas Present, living La Vida Victorian for two to four hours a day, depending on whether they have to pull a double shift — a matinee and evening show.

The thrill of live performance

A conversation reveals they are more interested in storytelling than accolades. They approach their roles thoughtfully, sometimes with a perception beyond their years.

In a time when every kid with a microphone, a bedroom mirror and access to YouTube dreams of being a reality TV star a la “American Idol,” these guys are old-school daredevils, walking the “do it live” tightrope. And that thrill is scary, but also part of the fun, they say.

“You can’t pause it or edit it,” McCormick said. “You really have to put in the work.”

Carroll says that while she’s done some commercials, theater is “the real deal. People are coming to see this live.”

She calls her character “the stereotypical annoying little sister. But she understands her family isn’t wealthy and she’s OK with that.” For her, a side benefit of “A Christmas Carol” has been “learning so much about this different era, its different speech and etiquette. You really feel it wearing aprons and shawls.”

To get a better feel for the characters, McCormick said he likes “to think about what they might do in their free time. Go to the store, pick out some food, hang with friends.”

“The show must go on,” said Hunter, intoning the theater’s most basic mantra. “There’s something new about every performance. And it’s fun to be a different person than yourself for a while.”

“People make mistakes and that can make the play better because the audience connects with that,” Carroll said. “That’s why when the dad [Bob Cratchit, played by Kris Nelson] said live one time, ‘Merry Scrooge, Mr. Christmas!’ it became part of the show.”

There are 15 juveniles in the show’s cast, making it one of the better high-visibility opportunities in town for aspiring young actors. But as one of the top regional theater markets in the country, the Twin Cities offers more training and chances to be in professional productions than do many other metro areas of similar size.

Jen Ritter, a producer for the Children’s Theatre Company, said one reason is that the area’s schools are extra-supportive of extracurricular arts activities.

“It’s a huge commitment for these kids and their families, including the time they have to take off to be in matinees,” she said. “The schools really seem to embrace the value of a holistic education.”

The making of a Tiny Tim

“God bless us, every one!” chirps Dregni at the end of a scene, uttering the show’s most famous line with a slight, high-pitched quaver.

“Nice work with the crutch, Otto,” says director Joe Chvala.

Chvala said he gives his younger performers “a little more time and encouragement, because they’re still learning how to act.”

Watching them interact with the older cast members, you wouldn’t know it. Though they’d rehearsed together only three times before, the younger actors displayed the same professionalism and esprit de corps as the adults.

The role of Tiny Tim might seem a breeze given its built-in adorability. Still, it takes a few certain somethings to land that part at the Guthrie.

“First of all, he has to be tiny,” said Chvala. “He also has to be a very natural and sincere actor, not too broad or over the top. He has to be able to learn to walk with a crutch and a brace, and the actor also has to sing pretty well for this production. Otto has all those qualities.”

For Dregni, the toughest part of the show is a tactile matter.

“The clothes really itch,” he said. “But I guess I just have to live through it.”