Simon Cowell stunned Britain’s Got Talent judges and fans by appearing on stage during auditions in Birmingham.

Louis Walsh was standing in for the media mogul after he was forced to call in sick with the flu.

An onlooker told the Daily Mail that fans went into a frenzy when Cowell walked on stage to face fellow judges Piers Morgan and Amanda Holden.

“He said, ‘My name is Simon and I am from London and today I am here to remove Louis Walsh from the panel’. The audience went barmy. Everybody went wild,” the source said.

Cowell, who was given the red buzzer from both Morgan and Walsh, then attempted to remove the Irish judge from his seat. Britain’s Got Talent returns to ITV1 in May.