Simon Cowell has admitted he was caught out by the success of Susan Boyle and said her debut on Britain's Got Talent left him looking "like a complete idiot".
The Scottish singer stunned Cowell and fellow judges Piers Morgan and Amanda Holden with her rendition of I Dreamed A Dream.
It made her an international star and last year it was reported it was the most watched clip on YouTube.
Cowell told Steve Wright on his Radio 2 show that he had no idea who would be appearing that day.
He said: "It wasn't a great day, she came on and I thought I don't think this is going to be great, I've just got a feeling here, and she started to sing.
"I didn't think at the time, to be honest with you, that this was incredible. I remember thinking this is great but Piers and Amanda got it more than I did and then when I watched the clip back and I saw the whole story, that is when I thought this is going to be huge and I'm going to look like a complete idiot."
He also branded former Velvet Underground frontman Lou Reed "petty" for not allowing Boyle to perform his song Perfect Day.
He said: "She was supposed to be on America's Got Talent this week. We've flown her over and she is going to perform Perfect Day by Lou Reed.
"Two hours before she is going to perform it we get a phone call. Lou Reed will not allow her to sing Perfect Day."