No, it's not just any ordinary birthday, its Justin Bieber's 21^st birthday! It's a big deal of course not only because Bieber is one of the most famous young pop stars today but because the world has witnessed the hit 'Baby' singer grow up.

The famous 'Boy Wonder' is now finally endowed with legal capacity to enter in several legal contracts and whatsoever. Bieber fans, especially those so called 'Beliebers' remember his days flipping his hair singing his hit songs, however, he is finally a grown man.

Thousands of Bieber's fans posted on the pop star's Twitter page speaking only good things for the 21-year-old. "21. To the fans' eyes, he wasn't just a popstar but he was a hero to many, many people. That's justin drew bieber. #21ReasonsWhyWeLoveJustin," one wrote on his Twitter.

Another post greeted Bieber a Happy Birthday writing, "I want to say happy birthday to an important friend and role model. This guy may be a tool, but he's my tool. Happy B-Day, @justinbieber!" Meanwhile, some Beliebers couldn't help but express their love for their idol.

"Happy Birthday to the love of my life i love you so much i can't believe that you are 21 my lifesaver@justinbieber," one wrote on her Twitter while another one wrote saying that being a Belieber is the best decision she made.

"You're my life saver @justinbieber and being a belieber is the best decision I have ever made. I will stay by your side forever HBD," one fan wrote. And as the Twitter world celebrates his 21^st year, Bieber had a birthday bash for himself as well.

Bieber reportedly celebrated with his closest friends including his rumored girlfriend and model Hailey Baldwin who posted a photo of her wrapping her arms around the shirtless Bieber. Several of their friends came and partied including Matthew Espinosa, Soundz, Yovanna Ventura and Ryan Butler.