Sshhhh... X Factor semi-finalists Joe McElderry, Stacey Solomon, Danyl Johnson and Olly Murs have played a top-secret gig in London.
Each of the semi-finalists sang two songs for the lucky competition winners. Don't Stop Believing was one of Joe McElderry's songs.
Here's Stacey performing! When asked who she thought would win X Factor, she said: "We are all winners!"
Olly strikes a pose as he sings his heart out!
Check out Danyl! He said his least favourite celeb guest on the show so far was Whitney Houston.