After Two Teen Boys "Choir" Opened Their Mouths, What Happened Next Surprised Simon Totally!

<p>Those teen boys always refresh audience with their sincere and amazing performance. The effect of the harmony, the sheer numbers, the dynamics and spirit of the young men are really awesome. Even if you've watched this 100 million times, you'll be still so thrilled. Just seeing people with tears in their eyes, you can tell that this song moved people deeply.</p>