NBC sets Dec. 9 as return date for season four of 'The Sing-Off'

Annual holiday series showcases the country's top a cappella groups

NBC has set Monday, Dec. 9 (9-11 p.m.), as the premiere episode of the new season of the holiday series "The Sing-Off."

"The Sing-Off" originally premiered in December 2009 as a five-night event and became a weekly series in 2011.

This year's season will run for seven episodes, with the finale set for telecast on Monday, Dec. 23, with a two-hour episode (9-11 p.m.)

The program showcases the country's top a cappella groups performing popular songs in ways that viewers have never heard them before. "The Sing-Off" has no lip-synching, back-up bands or safety net. They are singing with dreams of walking away with the ultimate prize: a recording contract and $100,000.

Nick Lachey will return as host. As previously announced, Jewel will join the judges table this season alongside Ben Folds and Shawn Stockman, who are both returning.