X Factor - Semi Final Special Guests!!

The semi final had some very special performances with an ex-winner and the cast of one of THE hottest shows in the US. Click through to check out the videos.

First up is Alexandra Burke (Series 5 winner) with her new track The Silence



Next up is the cast of GLEE with their performance of Don't Stop Believing ... I really can't wait to see them live next July!



And finally, we have the Black Eyed Peas who sang (badly) their new single The Time (Dirty Bit). It won't let me embed the video for that performance, but you can click here to view it over on YouTube.