'Clash of the Choirs' is a live four-night musical event coming to NBC in December 17th. "Clash of the Choirs," has tapped five musical superstars -- Michael Bolton, Patti LaBelle, Nick Lachey, Kelly Rowland and Blake Shelton -- to embark on a musical challenge as they return to their hometowns to assemble an amateur choir and prepare them to compete live in studio for the title of America's best choir. The show will feature music genres ranging from current pop hits to holiday classics. The choir hopefuls will be judged each night by viewers watching at home. Watch tonight on 8/7c !