Pentatonix is becoming a Christmas-music-making machine.

This year, the a cappella wizards re-released their uber-popular 2016 album “A Pentatonix Christmas” under the new, splashier and, uh, deluxe-ier name “A Pentatonix Christmas Album Deluxe.”

That follows on the heels of their 2014 CD “That’s Christmas To Me,” which ended up being the fourth best-selling album of the year. Fourth! It trailed only Taylor Swift’s “1989,” the “Frozen” soundtrack and Sam Smith’s “In the Lonely Hour.”

The group has conquered the world of TV holiday specials, too, with “A Pentatonix Christmas Special” last year on NBC and “A Very Pentatonix Christmas” last week, also on NBC. (Okay, the might want to branch out in terms of the show titles …)

They are, naturally, out on a Christmas tour, which is playing Mohegan Sun Arena on Saturday and Sunday. Fans can enjoy Pentatonix’s new vocalist, Matt Sallee, who joined after Avi Kaplan left in May (Kaplan said he was overwhelmed by Pentatonix’s “fast pace”).. He’ll join the long-timers Mitch Grassi, Scott Hoying, Kirstin Maldonado and Kevin Olusola.

A Pentatonix Christmas Tour, 7 p.m. Saturday and Sunday, Mohegan Sun Arena; $45, $65; 1-800-745-3000.