*Shawn Stockman of Boyz II Men joins the panel of celebrity judges tapped for NBC’s second round of “The Sing-Off,” a five-night event premiering Monday, Dec. 6 (8-10 p.m. ET), hosted by multi-platinum recording artist, Nick Lachey.

The one-of-a-kind battle of voices will continue on December 8, 13 and 15, culminating with a live finale on Dec. 20 (8-10 p.m. ET).

Other returning celebrity judges include Ben Folds (Ben Folds Five) and Nicole Scherzinger (“The Pussycat Dolls”).

NBC notes, “The show will feature the country’s top ten a cappella groups performing popular songs like you’ve never heard them before. There’s no lip-synching, back-up bands or safety net. They’ll be singing for America’s vote with the winner walking away with the ultimate prize – $100,000 and a Sony Music recording contract.”

The ten groups who are competing this year are:

The Backbeats – Los Angeles, CA
Composed of the best a capella singers from University of Southern California and University of California Los Angeles, the group of twenty-something’s incorporates their disparate styles and tastes into one synthesized sound fused together by their love of Pop, R&B and Soul. Backbeat has a fresh, original approach to popular music with that old school spirit.

Eleventh Hour – Kettering, Ohio
Recognized as one of the nation’s top high school a cappella groups, their studio recordings have been featured on Best of High School A Cappella and have won two Contemporary A Cappella Recording Academy awards. Eleventh Hour has opened for LeAnn Rimes, The Beach Boys and sang backup for Kenny Loggins. Their youth and energy combine with musicianship that is beyond their years.

Pitch Slapped – Boston, Massachusetts.
Founded in 2006, the group of students from Berklee College of Music has won numerous International Championship of Collegiate A Cappella awards, including their recent triumph of 2nd place overall. Pitch Slapped offers a distinctive sound and infectious energy, with a unique grasp on a cappella and have a sense of musicality that is apparent in their arrangements, solos, and overall sound.

Groove For Thought – Seattle, Washington
Since the group’s inception in 1998, Groove For Thought brings their unique brand of jazz and R&B infused tunes to festival, concert, school, and nightclub audiences throughout the United States and abroad. The group won the National Harmony Sweepstakes Championship in 2005 and the Contemporary A Cappella Recording Award for Best Jazz Song in 2006.

Men of Note – Cherry Hill, New Jersey
This all-male group of eight is comprised of Cherry Hill High School West alumni, where the group was first founded. The three-time winners of the Best Of High School A Capella competition, the group has the perfect mix of originality and diversity.

Street Corner Symphony – Nashville, Tennessee
Formed in May of 2010, the group of six contains two sets of siblings. All from the Southeast U.S., the members bring a unique laid back southern soul to the group. Street Corner Symphony offers a diverse repertoire, while maintaining their rich heritage in gospel music.