Justin Bieber's emotional 2015 MTV Video Music Awards performance has left so many people who witnessed the event baffled. Now, the 21-year-old Canadian pop singer has finally revealed the reason to one of the biggest mysteries in the MTV VMA history.

On Sunday night, many fans and avid MTV VMA viewers wondered why Justin Bieber broke down in tears following his medley performance of the songs, "Where Are U Now?" and "What Do You Mean." So, during his guest appearance on Jimmy Fallon's "The Tonight Show" on Wednesday night, Bieber took the opportunity and confessed the reason why he got so emotional during the VMAs, CNN reported.

"It was so overwhelming for me, everything - just the performance," Bieber said. "I missed some cues, so I was a little disappointed at that, and just everyone and just their support. I was, honestly-let me breathe for a second-I just wasn't expecting them to support me in the way they did. Last time I was at an awards' show, I was booed."

Justin Bieber, whose Sunday night MTV VMA performance was his first in five years, also admitted that the positive response he got from the crowd had blown him away and the support totally surprised him, Access Hollywood noted.

 "I think it's just like I've worked so hard at this album, I've worked so hard at just becoming the man I want to become, and then stepping into situations, you just can't help but feel judged," he continued, as per Rolling Stone. "So, I was just feeling judged and wanting to win so badly, and just wanting to do what I love so badly that I just put everything on the line. And I think that that was what was so special about the emotional moment at the end, that it was authentic. It was real. It was like I was really just wanting it so bad."

In addition to his explanation for his tearful VMA performance, Justin Bieber also candidly talked about his past troubles with the law.

"What it was is that I had a bunch of knuckleheads around me; that was pretty much it," Bieber told Fallon. "[It's] never good to have knuckleheads around. I just went through a place of just trying to figure it out and making decisions. You have to figure out what you're OK with and you're not OK with, but you have to test the waters. I just happened to be in the spotlight, in front of cameras all the time, and they caught all those moments."

While everyone was curious about the real reason behind Justin Bieber's VMA tears, others were searching for his ex, Selena Gomez's reaction. Unfortunately, Gomez and her friend Taylor Swift had exited the venue before Bieber's emotional production number, as previously reported.