It was a surprise to all her fans when the singer ran off the stage in the middle of a song. 

Miley disappeared for 15 minutes and no one knew what had happened to her. It looks like she has a throat infection, and then she said later on Twitter, that her voice just couldn't take all the singing, which is why she left the stage and basically, could not sing any more. 

After 15 minutes and some water, Miley returned and finished the show. 

Here's a video of her as she leaves the stage. We know the quality of the video is not the best, but you can hear that she is having trouble with her voice. We hope she feels better soon.