Cee Lo Green and Adam Levine have signed on as judges for the Mark Burnett–produced singing competition The Voice, premiering April 26 on NBC. There’s still one judge's seat left to fill, and Christina Aguilera is a rumored contender for the spot. The show is a potential rival to Fox's American Idol. “We want The Voice to be a search by relevant artists for relevant artists,” said NBC's Paul Telegdy. Burn!