18-year-old [tag]Joe Cox[/tag] had originally made the judges' houses stage of the competition last year, but wasn't chosen by mentor [tag]Gary Barlow[/tag] to go through to the live shows.
Undeterred, the teenager returned back to the audition stage to sing again for Gary and the other judges in London.
Joe told the panel: "I want to say thank you for saying no, because I wasn't ready.
"Now I've had a year to think about it, I know you did me the biggest favour of my life. Last year I felt like a nervous little boy, and now I've come back a man."
After performing a unique cover of Katy Perry's The One That Got Away for the panel, the judges were impressed.
Louis raved: "You've convinced me we've found someone brilliant. I predict you are one of the people to watch in this competition because you are bigger and better."
Tulisa gushed: "I really felt that as you were singing it, and if you were in my category last year you'd have been in the live shows."
New judge Nicole added: "This is why I'm so happy to be back in the UK. You have an excellent recording voice."
While Gary said he had been "waiting for this moment".
The Take That star told Joe: "Your 'no' was the hardest for me by far and I've been waiting for this moment. You are going to be a great artist Joe, welcome back."
The X Factor returns to ITV1 in the summer.
Watch [tag]Joe Cox[/tag] back on The X Factor 2012 below...