Justin Bieber performed four songs, including 'Boyfriend' and 'Baby' on 'TODAY' this morning (June 15), bringing his swag, swag, swag with him. He was interviewed about growing up and even helped host Matt Lauer make the leap to the 21st century via Twitter.

Beliebers were waiting for him outside Rockefeller Center in N.Y.C. since Tuesday. When he had a moment off, he rewarded them for their loyalty and dedication by visiting them early.

When Matt Lauer interviewed the singer before he performed the four-song set, the Biebs said that he doesn't get stressed by the melees and mobs that surround him, saying, "Security knows how to keep them back and keeping them at a safe distance, but my fans are not trying to hurt me." Lauer joked he meant the smell, since the gathered Beliebers had not showered in a few days. That doesn't bother the Biebs either, though.

Lauer spoke about how 'Believe' marks his transition from teen phenom to adult artist, which Bieber acknowledged. "I'm 18 and have a lot of insecurities," he said. "At the end of the day, me being in my position doesn't get rid of those insecurities. Coming out with this album, I've been working hard on it, so I am confident in the album."

He continued, "I think [this album] is about proving people wrong and going out there and making good music and going out there and performing better than everyone else. That's what I have to do to cross over [to being an adult performer]. Or else I'll just be another teen heartthrob, and I want to be remembered."

Lauer mentioned manager Scooter Braun's quote about how Bieber is no longer a boy, but not yet a man (a la Britney's famous 'Crossroads' track). That didn't offend the teen, who said, "I agree with him. I am still growing up and learning different things. I am not all the way there. My fans are growing with me."

Oh, and that whole running into a glass wall and getting a concussion thing? That was mentioned, too. "I'm pretty clumsy and I don't see glass walls," Bieber joked. "I think I wasn't wired to see glass walls." He's OK now, and he's used to it since this isn't his first head trauma: "I'm all right. I've had concussions, I used to play hockey."

The Biebs also helped Twitter virgin Matt Lauer send his first tweet, since he just joined the social media messaging service. Lauer wanted to see the "power of Bieber," with a producer promising that he'd streak in the studio if Lauer racked up 750,000 followers by next Tuesday, thanks to Bieber's urging.

Some shameless self-promo took place, with the singer sending out a tweet urging Lauer followers to buy 'Believe.' Minutes later, Lauer was trending. That's the power of the Biebs.

Thousands of screaming, crying Beliebers packed NYC for the perf. Wearing a white vest with zippers (sorta Michael Jackson-like) and black, fingerless gloves (also sorta Jackson-like), he looked good and sounded and danced better.

For 'Baby,' Biebs turned the song into an adult version, surrounded by dancers. It was the dance moves that gave this song a grown up boost. During 'As Long As You Love Me,' he was strutting up and down that stage, touching fans' hands, which we know they will never wash again. The camera panned to lots of crying faces. Big Sean, in a leather hoodie, joined Bieber for his part of the song. We love that Beliebers already know ALL the words to these songs that JUST dropped.

We gotta hand it to Jamaica, Bieber's choreographer -- she has taught him some mature moves. During 'Boyfriend,' that leg action when he's singing "Chillin' by the fire when we eatin' fondue?" Whoa! What a groove.

These four songs shows us that dancing is a crucial element of Bieber's shows now. Was that shuffling we saw? Yeah, it was.

Watch Justin Bieber Perform 'Baby'

Watch Justin Bieber Perform 'As Long As You Love Me'

Watch Justin Bieber Perform 'Boyfriend'

Watch Justin Bieber Perform 'All Around the World'

Watch Justin Bieber Talk Glass Walls + Help Matt Lauer Trend on Twitter

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