American Idol’s final four took to the stage as they bid to rock their way to the semi-finals. However, the show was almost wrecked before it even began after an incident almost jeopardized the show going on air.

Host Ryan Seacrest kicked off the show explaining that there was an accident on the stage before dress rehearsal, with one of the towers on stage COLLAPSING just minutes before going on air, with the contestants having to go straight into their live performances without a dress rehearsal.

Not one to let pressure get to him, the first performer is Adam Lambert, who sings Led Zeppelin’s Whole Lotta Love – which once again left Simon Cowell lavishing praise on the series favourite. Cowell told him “it could have been a disaster, but it ended up being one of his favorite performances” adding that “the problem is that no one can top it”. Seacrest says it’s the first time a Zeppelin song has been performed on American Idol. Paula Abdul tells him he’s a “whole lotta perfect.”

16 year-old Allison Iraheta is up next singing Janis Joplin’s Cry Baby. Abdul says “if they ever do a biopic on Janis Joplin she’s got the role” while Cowell says “the difference now from eight weeks ago is staggering”, though adds that she “should have chosen a Queen song.” She tries to explain her song choice while Cowell teases her, telling her “she likes the fact that she’s arguing for herself.” It also appears that Cowell is holding a LIGHTER in his hand while he’s giving her feedback
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For the first time this series, two contestants perform a duet, with Kris Allen and Danny Gokey singing Styx’s Renegade. Judge Kara DioGuardi says the song “Renegade” was “funny since they’re the guys who help little old ladies cross the road”, while Abdul says it was “compelling.” Cowell kicks up the rivalry, saying “OK, Danny was better than Kris, how’s that?”

Allen is next up to sing solo, singing Come Together by The Beatles, however, he failed to earn praise from the judges, with DioGuardi telling him “it didn’t do it for me”, Abdul telling he “needs to have a little more energy” – and Cowell telling him “”I didn’t really like it. It was like eating ice for lunch.”

Danny Gokey is next, singing Dream On by Aerosmith – with the song ending in a high-pitched scream, leaving Cowell to respond “That scream at the end? It was like watching a horror film.”

The final performance of the show was a duet with Iraheta and Lambert singing Slow Ride by Foghat. Cowell says “they win the battle of the duets” and that “Adam may have given Allison a chance to stay in the competition as a result.”

The results will be announced on Friday night’s show on ITV2 – with the three semi-finalists being revealed, and will also include a performance from Paula Abdul, who has announced she will perform her new single, “I’m Just (Here for the Music),” live on stage. Abdul told US magazine TV Guide, she was hesitant to take up the show’s producers when they made the last-minute offer. “I wasn’t sure if I was going to do it. Timing was of the essence,” she said. “I put everything together on Saturday and rehearsed on Sunday. It was really good, and I am feeling good about it… There’s a lot to see in less than three minutes.”