'The Sing-Off' returns to NBC with six new groups competing in two-hour holiday special Dec. 17

Jewel, Shawn Stockman and Patrick Stump serve as judges with Nick Lachey returning as host

NBC will air a two-hour holiday special of its popular a-capella musical competition series "The Sing-Off" Wednesday, Dec. 17 (9-11 p.m. ET/PT). Six new groups will compete for a first-place prize of $50,000.

Returning judges Jewel and Shawn Stockman will be joined by Fall Out Boy frontman Patrick Stump, while Nick Lachey is once again set as host.

Last year's "Sing-Off" champions, Home Free, saw their recent album release, "Crazy Life," go to No. 1 on the country iTunes chart and No. 4 on the overall iTunes chart. They embarked on a 36-show tour in support of the album and have appeared on shows such as "Today" and "Fox and Friends."

As another sign of the influence of "The Sing-Off," Pentatonix have become a musical force since winning the third season. Since their debut in 2011, the quintet has released four EPs, and its first full-length holiday CD, "That's Christmas To Me," selling more than 600,000 copies combined with three of the releases debuting in the Top 10 on Billboard's Top 200 chart. Having recently eclipsed 6.6 million subscribers and 625 million cumulative views, the Pentatonix official YouTube page is currently the 13th most subscribed-to music channel, having surpassed the subscriber totals of both Avicii and Beyoncé.

Fans can visit the official show site at http://www.nbc.com/sing-off/.