The who's who of young Hollywood was in attendance!

Cody Simpson celebrated turning another year older with a birthday bash at The Nice Guy in Hollywood, and girlfriend Gigi Hadid was there along with Miley Cyrus and boyfriend Patrick Schwarzenegger and Justin Bieber. The Australian singer was presented with a pepperoni pizza cake, and it looks like it was quite the wild night!

The blonde pop star is the least famous of this whole crew, but it sounds like he might looking to raise his star power this coming year. "I'm putting together a pretty cool catalog of music. I moved record labels, so I kind of get a fresh start now doing it the way I wanna do it because now I'm kinda old enough to have the creative freedom and the tools to do it the way I wanted to do it," he recently told E! News.

If Kendall Jenner and Hailey Baldwin had been there, it would have been the whole "It" crowd of teens in the spotlight!