Justin Bieber, 16, has officially taken Will's son Jaden Smith 12 years under his wing. The two young stars, is busy preparing for the performance of a Grammy along with Usher, has ties all weekend as Justin showed Jaden rope.

"Justin is still young, but he dealt with both joys and pitfalls of fame," the source said backstage at the Grammy PopEater. "He plays older brother, and make sure Jayden ready for what will 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."