Justin Bieber and Jaden Smith Bro Out at Coachella, Share Kiss

Justin Bieber and Jaden Smith are still friends after all these years ... with Jaden grippin' Justin in a big hug and gettin' a smooch in return during Coachella.

The two music superstars met up Saturday during the music festival's busy first weekend ... and, JS decided to surprise his best bro by embracing him from behind.

Check out the clip ... Bieber's face lights up when he looks back and sees it's Jaden who decides to move around and go for a real embrace from JB in a VIP area at the festival.

That's when Justin plants a quick kiss on Jaden's cheek before breaking apart and catching up with his longtime friend ... a sweet moment between two former child stars.

Remember ... Jaden and Justin's bromance began way back in 2010 when they collaborated on the song "Never Say Never" for Jaden's hit "Karate Kid" remake.

The two hit it off and have been constant presences in each other's lives ever since, despite their five-year age gap. They've performed together several times and generally hung out in the past decade.

BTW ... neither Jaden nor Justin took the stage Saturday -- but, that's not totally shocking 'cause they're just huge fans of the music festival. They both attended last year too, so it seems like a yearly outing for each of them.