"The Sing Off' courtesy NBC photo ©Sony PicturesTelevision

NBC’s The Sing-Off is looking for the best-of-the-best a cappella groups to audition for season three of the hit series.

Casting for the vocal competition show has amplified and expanded to five different U.S. cities over seven days to discover the most talented a cappella groups to compete for an opportunity to win a cash prize and a Sony Music recording contract.

Casting call cities and dates are: Boston on May 5, NYC on May 7, Nashville on May 14, Chicago on May 21 and L.A. on June 4.

More info at http://www.facebook.com/singoff and on twitter @thesingoff.