The 22-year-old singer explained his "authentic" crying on Sunday, Aug. 30, was the result of wanting things to go right so badly, and then managing to mess up a couple of moments of his performance.
Revealing to Fallon that he'd been booed at the last awards ceremony he attended, an emotionally sensitive Bieber says he was trying so hard to give the performance of a lifetime, to turn people's opinions around, that it all got too much for him.
"It was just so overwhelming for me," the "Baby" singer explained. "Everything, the performance, I missed some cues so I was a little disappointed with that," he added.
"And everyone — the support — I was honestly wasn't expecting them to support me in the way they did. Last time I was at an awards show I was booed. I've worked so hard at this album, I've worked so hard at becoming the man I want to become. Then, standing in the situation, you just can't help but feel judged, so I was just feeling judged and wanting to win so badly, and wanting to do what I love so badly, that I just put everything on the line," he continued.
"I think that what was so special about that emotional moment at the end was, it was authentic, it was real. I was really just wanting it so bad — I'm just ranting now," he added, laughing.
Fallon then went on to ask the former teen sensation about his transformation from a wild child to the man he is today.
"I just had a bunch of knuckleheads around me," he said. "That was pretty much it. You have to figure out what you are okay with and what you're not okay with, but you have to test the waters. I just happen to be in front of a spotlight and they caught all those moments."
Fallon's audience started to laugh at Bieber's attempts to justify his, at times, extreme and illegal behavior.
"Hey, don't laugh," he said to the crowd. "You guys saying you didn't have those moments?"
"Not as much as you!" replied Fallon.
Watch the whole interview in the video above.
Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!