Justin Bieber and Jaden SmithJustin Bieber, 16, has officially taken Will Smith's 12-year-old son Jaden under his wing. The two young stars, busy preparing for a Grammys performance together with Usher, have been bonding all weekend as Justin shows Jaden the ropes.

"Justin is still young, but he's dealt with both the joys and pitfalls of fame," a source backstage at the Grammys tells PopEater. "He is playing big brother, and making sure Jayden is prepared for what's to come."

The pals, who collaborated last year on Bieber's single 'Never Say Never,' have also been hanging out off stage too, showing up to random theaters in Los Angeles to surprise fans attending Bieber's new 3D movie, 'Never Say Never.'

With Usher mentoring both singers and anchoring their Grammys performance, the two are in good hands as they get ready to hit the stage on Sunday night. "The performance will be fun," the source says, adding that the number will feature Bieber playing acoustically, before a segue into a more uptempo groove. "This is Justin's moment to show the world, especially those who never believed in him, that he's very talented. Trust me, you won't want to miss this one."