L.A. Reid regrets dropping Lady Gaga

Lady Gaga's success will forever irk music mogul Antonio 'L.A' Reid - because dropping her from his record label was the "worst thing" he has ever done.

The X Factor judge signed the star up while she was still a struggling singer, but later dismissed her from his roster when he was "having a bad day".

The Poker Face hitmaker went on to sign with another label and shot to international stardom, and Reid admits he made a big mistake letting Gaga go.

He tells Access Hollywood, "This artist came to my office... she played piano, she had on white go-go boots - like, all the way up to here, thigh high boots - she sat down at that piano, she played and she sang. When she was done, I said, 'You are an amazing artist, a true star, and you will change music,' and I signed her. Her name was Lady Gaga.

"Then, a few months later, I got her demos, and it was a work in progress, and I was having a bad day. I'm telling you, I was having a bad day. And I said, 'You know what? I really don't like it. Let her have her freedom, let her go find her career.' It was the worst thing I've ever done."

However, a month later the former Island Def Jam Music Group chairman "redeemed" himself by signing teen sensation Justin Bieber.

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