From left, Usher, Shakira, Adam Levine, and Blake Shelton arrive at "The Voice" season 4 red carpet event at the House of Blues on Wednesday, May 8, 2013 in Los Angeles. (Photo by Matt ... more 
From left, Usher, Shakira, Adam Levine, and Blake Shelton arrive at "The Voice" season 4 red carpet event at the House of Blues on Wednesday, May 8, 2013 in Los Angeles. (Photo by Matt Sayles/Invision/AP) less 
1 / 30
Associated Press
Thu, May 9, 2013 5:09 AM EDT