He earned a reputation as Judge Dread on "American Idol," but Simon Cowell's criticism of a contestant on his British show "X Factor" has turned him into a lifesaver!

After contestant Jacqui Gray finished singing her heart out, Simon warned, "Something weird happens to your throat when you sing."

The hopeful singer went to the doctor - and found a potentially fatal lung disease. Gray reportedly says she owes Simon her life because he caught it early!

Now Simon is giving "Extra" the details of the heroic story, happily admitting, "I saved her life."

"We said, 'I think you'd better get your throat checked out,'" he added. "So she did and the doctor found out she had something really serious, and she could've died."

So has the lucky contestant been in touch with Simon?

"No, but I'm sure she will be," he said.