SXSW, the world's biggest music showcase festival, is currently taking place in Austin, Texas.

The festival has a habit of throwing up some surprise appearances and guest slots - like that time that Bill Murray partied with Wu Tang Clan and crashed a house party where a band were playing.

Well, last night threw up another surprise when Miley Cyrus appeared on stage for Mike WiLL Made-It's performance at the festival with a super soaker water gun, singing/rapping snippets of her songs '23' and 'We Can't Stop', and generally having a good ol' time.

A very good time, in fact: at one point between songs, she mentions being drunk and says "This is Texas. I don’t know how f*cking high you are, but we’re high as f*ck up here.”

Watch the video below, but beware of some fairly hefty NSFW language. Hope you drank a pint of water before you went to bed, Miley.