Simon Cowell reflects on his first interaction with Kelly Clarkson on 'American' Idol'

Simon Cowell shared her first meeting with Kelly Clarkson on American Idol and the role she played in making the reality singing competition into the success it is today.

On Tuesday, the Since U Been Gone singer was honored with a star on the Hollywood Walk of Fame. During the ceremony, former Idol judge Cowell delivered a speech in her honor.

"I actually thought I was being punked on the first day. Paula [Abdul] resigned, every singer was out of tune, and I thought, 'Well this is a joke.' It got worse, progressively," Cowell, 61, said. "So I thought this is an absolute disaster. Like, why did I come here?"

He continued to Clarkson, 40, "And thank God, I remember the day we met you. I remember not just your voice, but your personality. I'm gonna be honest here, I didn't realize at that point, honestly how good you were. I just liked you. And I was so thankful."

The America's Got Talent judge then went on to compliment her character and thanked her for being the reason Idol became such a success.

"I remember that moment when your name was called, and I was thinking to myself, 'Thanks to you, we may have another season.' I can honestly say to you, thanks to you. You validated what we did, because if we didn't find a star, there was no point in doing these shows," Cowell said.

Former Idol judges Paula Abdul, Randy Jackson, producer Jason Holler and friends and family of Clarkson were in attendance at the ceremony.