(Cover) - EN Showbiz - L.A. Reid has confessed that letting Lady Gaga go was "the worst thing" he's ever done.

The music mogul and X Factor judge has discovered artists such as Pink, Usher and Rihanna.

However, L.A. admits that his biggest regret is failing to take a chance on the Born This Way Singer.

"This artist came to my office," L.A. told Access Hollywood. "She played piano, she had on white go-go boots, she played and she sang. When she was done, I said, You're an amazing artist, a true star, and you will change music,' and I signed her. Her name was Lady Gaga."

But things quickly turned sour between the pair. A few months later L.A. received some of her demos.

"I said, You know what? I really don't like it,'" he revealed. "'Let her have freedom, let her go find her career.' It was the worst thing I've ever done."

A month later a certain 14-year-old Canadian singer appeared in the music mogul's office. L.A. again felt the thrill of discovering a huge star.

"I felt bad," he admits. "But I swear to you like a month later Justin Bieber came and redeemed me, so, you know I survived it."

L.A. now only feels the pangs of regret when looking at Lady Gaga's huge fan base on Twitter. Although Justin has an enormous following, L.A. acknowledges that he'd of like to have them both under his belt.

"I'm a little bit jealous, because the Twitter following, for example, the biggest ones are Bieber and Lady Gaga, so I would have felt like the king of the world! Instead I felt like half the king," he laughed. (C) Cover Media