Leona Lewis and Carrie Underwood are two superstars Simon says he knew would hit it big the moment he met them. "It's more than a voice; you've got to have 'it,'" he says. "It's rare, and I'm glad that it's rare, because these people should be like diamonds."
Simon's brutal honesty made him famous, but he says he never plans his comments for contestants ahead of time. "The best way of approaching it is to be in the moment," he says. "Then, hopefully you will be saying what people at home are going to be thinking."