The 64-year-old judge reportedly rushed to check on the contestant, who had suffered a fall and was “in agony”.
Filming was halted for an hour due to the twenty-something man's 'shock collapse', but only after the rest of the troupe had completed the routine, unaware of the severity of the injury.
He was attended to by doctors on set “as a precaution”, according to the ITV programme.
Fellow judge Bruni Tonioli joined Simon backstage to check on the man, while Alesha Dixon and Amanda Holden awaited updates with the audience.
A source said The sun: 'It was a real shock when this happened as the lad, who was in his early twenties, was obviously in agony.
“Unfortunately, the rest of the troupe were so focused, and there were so many of them, that they completed the routine before realizing how seriously injured he was.
“It is believed he had somehow aggravated an existing injury, but it was initially unclear what had happened.
'After the security curtain fell, Simon and fellow judge Bruno Tonioli went backstage to check on the lad.'
A Britain's Got Talent spokesperson said: “The health and safety of our contestants is of the utmost importance.
“A member of a dance group suffered an injury during the audition and was attended to by doctors on set as a precaution.”
This happened after a source said Metro.co.uk claims that Simon was forced to miss a series of tests for the upcoming series due to a debilitating headache.Completely over-the-top rubbish that is deliberately over-the-top.”
Speaking last week, the source continued: “He wasn’t filming last week anyway.
'The week before he filmed all week, but on Wednesday, very late at night, Simon had a migraine because of the bright lights from filming and only missed two acts at the end of the day.
“He went back to filming the next day and for the rest of the week.”
Simon's nine-year-old son Eric joined dad Simon at the London auditions for the talent show and the music mogul was left 'embarrassed' after the youngster made a very honest comment about an act.
When asked for his opinion, according to one viewer, Eric said: 'I didn't really like the first part, but I liked the second part.'
The mirror reported that Amanda took the opportunity to make a joke and told the crowd: 'He's a chip off the old block!'
Do you have a story?
If you've got a celebrity story, video or pictures get in touch with the Metro.co.uk entertainment team by emailing us email@example.com, calling 020 3615 2145 or visiting us Send stuff – we love hearing from you.
MORE: Simon Cowell's Britain's Got Talent illness claims dismissed as 'rubbish'
MORE: X Factor contestant still hasn't recovered from Simon Cowell's terrible comment