The old saying is true -- never judge a book by its cover.
But the 19-year-old swiftly brought the audience of "America's Got Talent" to tears and even received a standing ovation from the three judges -- Sharon Osbourne, Howard Stern and Howie Mandel -- with his soul-wrenching rendition of opera classic "O Mio Babbino Caro".
Showcasing his powerful pipes, it was clear that the audience was captivated by De Leon -- who described himself as a social outcast who claimed to have never sung in public before. Not even to his parents.
"Singing was always an escape… a comfort zone… [but] my days of being shy and being an outcast have reached their end, and I'd like to really show what I can do," said the self-taught singer to host Nick Cannon before his performance.
When asked by Stern on how he felt after his tear-jerking debut performance, De Leon said, "I'm just so used to being rejected and I'm not really good at anything so this is amazing" to which Osbourne replied, "Please don't say you're not good at anything because you've got an amazing voice. And you are an individual."
In another boost to a visibly nervous and overwhelmed De Leon, Mandel said, "You've been hiding in your room all these years but you've never let the world see who you are, or what you are… It's not that you're not good at anything. You are great."
After De Leon exited the stage to the hugs of his parents backstage, his mother was overheard saying, "You never told me you could sing like that".
Unsurprisingly, De Leon received three nods to his performance and will be flying to Las Vegas soon for his second audition.
Watch De Leon's performance here: