It’s hard to act and sing at the same time.

Now imagine having to act, sing and play a musical instrument simultaneously. That’s the unique challenge for the four actors who comprise the cast of Music Theatre of Madison’s upcoming production of "Striking 12," a modern, musical rendition of Hans Christensen Andersen’s classic holiday tale “The Little Matchstick Girl.” Instead of actors playing and singing the key roles while musicians offstage (or in a pit) provide accompaniment, the musicians inhabit the roles and speak the lines while seated at, standing behind or holding their instruments.

“It’s absolutely a challenge,” says Jason “Mac” MacPherson, the local guitarist who handles the guitar and bass parts of the score while providing vocal harmony and serving as the story’s narrator and “small parts” guy. Instead of a single script, MacPherson has to memorize the vocal book, the guitar book and the bass book for the show.

“I’ve worked in the pits for the last 20 years,” says MacPherson, who makes his living teaching guitar in his Madison studio. “I have not been on a stage in front of people before. It’s going to be interesting.”

MacPherson’s been in Madison for 14 years, and, in addition to "Striking 12," has been part of the orchestra for a raft of local productions, including Out!Cast’s recent production of "The Rocky Horror Show" and Middleton Players Theatre’s recent production of "Jesus Christ Superstar."

Striking 12 takes a modern twist on the classic Andersen tale. A disillusioned middle-class condo dweller (played by drummer Desmond Hawkins) determined to avoid celebrating the holidays is disrupted by a girl knocking on his door and hawking full-spectrum holiday light bulbs—just the thing for that seasonal affective disorder, right? He regrets his decision to send her away, but eventually discovers the holiday spirit. Spoken excerpts from Andersen’s story serve as segueways between several of the songs.

Erin McConnell, the show’s music director, who’ll play the piano and the part of the matchstick girl, says managing rehearsals has been an unusual experience. She’s used to working with actors for a month, and then bringing in the musicians for a separate session. Here, she’s doing both at the same time.

“it’s been a challenge to be present and also integrate myself into the process,” she says. ”It requires a lot of bandwidth. But it’s exciting to work with people whose first place isn’t acting. Letting them bring the story in has been interesting.”

The three-things-at-once piece has also been a personal curveball.

“We have to play music under the dialogue,” explains McConnell, who’s served as music director for a long list of local productions, including MTM’s 2015 production of "35MM."

“It’s hard to play something in meter and be talking conversationally over it. It’s like patting your head and rubbing your stomach at the same time. You have to bisect your brain.”

As has been the case with recent MTM productions, artistic director Meghan Randolph’s staging "Striking 12" in a series of unusual locations, starting with a free afternoon gig at Sequoya Library on Dec. 3, followed by free shows the following weekends at Middleton Library and Central Library. A pair of ticketed shows at The Brink Lounge wrap the run on Dec. 29-30, but no worries for parents concerned about the bar location; the show’s family-friendly and kids are allowed.