Justin Bieber got on stage Saturday night ... a big deal because it's his first full concert performance in 2 years ... and guess who closed the show?
Justin took the stage Saturday at KIIS FM's Wango Tango, 2015 in Carson, CA. Fans went crazy for 4 hours before Bieber took the stage at 8:30 PM.
Kanye closed the show, so it wasn't surprising his mother-in-law Kris Jenner was in the audience. A little surprising ... she was sitting next to Big Sean, who had beef with Bieber over the whole Ariana Grande hugging thing.
And Hailey Baldwin was also cheering Justin on ... there's a buzz the 2 have been dating.