What does it take to soften the soul of Simon Cowell, America's Got Talent's resident crotchety judge? A 13-year-old opera singer named Laura Bretan, apparently.Young Laura was a fit of nerves before her audition on the NBC talent show, and rightly so. Cowell is famous for his sneering dismissals of wannabe talent, and this season has been no exception. But by the end of her audition, the teen's talent was so moving that she won an audience of fans and melted Cowell's heart.Bretan performed a rendition of the aria "Nessun Dorma" (Italian for "None shall sleep"). If you watch close enough, you can see Cowell's icy demeanor soften as Bretan's voice ascends from the stage and straight into the stratosphere.Bretan is a hugely talented opera singer, but her skills as a live performer give goosebumps. "Nessun dorma" is a deeply poignant aria. It was made famous by Luciano Pavarotti two decades ago . And this teenage Breton just took it to new heights — and got a golden buzzer in the process.