NBC has announced Pussycat Dolls member Nicole Scherzinger will serve as the third judge for its four-night The Sing-Off reality singing competition, which will premiere Monday, December 14 at 8PM ET/PT.

Singer Ben Folds and Boyz II Men member Shawn Stockham had previously been revealed as members of the show's judging panel, however NBC originally announced a rotating guest judge would fill the third seat -- which will now be filled throughout the competition by Scherzinger.

Hosted by Nick Lachey, The Sing-Off will begin with the eight a cappella groups performing contemporary songs without the use of any backing tracks or instruments.

The performances will be critiqued by the judging panel, however home viewer votes cast following the broadcasts will determine which group receives the show's grand prize of $100,000 and an Epic Records/Sony Music recording contract.

The a cappella groups competing on The Sing-Off are Beelzebubs from Boston, MA, Noteworthy from Provo, UT, Face from Boulder, CO, Maxx Factor from Baltimore, MD, Nota from San Juan, PR, The SoCals from Los Angeles, CA, Solo from Omaha, NE, and Voices of Lee from Cleveland, TN.

NBC ordered The Sing-Off in March and it is being produced by Outlaw Entertainment, Tenth Planet Productions and Sony Pictures Television, with Joel Gallen, Deb Newmyer and Sam Weisman serving as executive producers.