Justin Bieber: Scooter Braun's 30th Birthday Bash!

Justin Bieber celebrates his manager Scooter Braun‘s 30th birthday at The Music Box Theater on Saturday (June 18) in Hollywood.

The 17-year-old singer performed with pal Jaden Smith, while Adam Levine, Usher, and surprise performer MC Hammer also hit the stage separately.

Usher served as Master of Ceremonies along with Scooter‘s brother Adam at the party, where close friends and family helped kick off the festivities by playfully roasting the birthday boy.

“The big day is here. you are an old man now @scooterbraun . lol. with love #HAPPYBIRTHDAYSCOOTER,” Justin tweeted.

30+ pictures inside of Justin Bieber, Usher, and more celebs attending Scooter Braun‘s 30th birthday bash…