Tyga was performing at California State University Northridge as part of the CSUN Big Show. Kylie shared some videos on Snapchat as she was hanging out just to the side of the stage, so we're not sure if the appearance was a surprise to Tyga or not.
Before she even arrived at the venue, she and her friend Jordyn Woods shared a Snapchat story, where Kylie shared that they were going on "an adventure," which lends itself well to the surprise theory.
This isn't the first time Kylie has made a cameo during one of her peeps' concerts. Last month, Pia Mia dragged Kylie on stage during her concert at City Walk in Los Angeles - and Kylie was actually super shy about the whole thing. This time, she seemed much happier about being on stage.
The last time Tyga performed on a college campus, there was a little situation about him not being allowed to bring Kylie to the venue because it was an 18-and-over event. He ended up bringing her anyway and while she ended up just chilling on the sidelines, it looks like she still had a pretty good time.