NBC renews 'The Sing-Off'

NBC's singing competition series "The Sing-Off" has been renewed for a second season.

The network is bringing back the Sony Pictures Television reality series for another eight episodes planned for next season.

The "Sing-Off" is an a cappella competition series where contestants perform in themed groups. The program had a competitive run when it launched in December as a short-order series, giving Fox's musical-themed reality hit "So You Think You Can Dance" a run for its money in the ratings.