After a 45-minute delay during the interval, director Sean Foley was forced to announce to the audience at the preview performance that the show would not go on.
Simon poses with Nigel Harman and 'I Can't Sing' writer Harry Hill
According to Digital Spy, audience members were offered a refund or new tickets for an alternative night.
A few audience members took to Twitter to voice their disappointment, with one writing: “I Can't Sing' at the London Palladium. Power problems back stage, caused Act 2 to be cancelled. A disappointment. Act 1 was very good”.
The music mogul helped finance the musical and is also one of the show’s co-producers.
He’s even been giving Nigel advice on how best to play the lead role, joking that he should “just be a d**k every night”.
The official ‘I Can’t Sing’ opening night takes place on 26 March 2014, however, fans can currently buy tickets for preview performances taking place before then.