The 32-year-old from Leeds has already amassed a great deal of experience in reality contests, having reached the final of Fame Academy in 2003 as well as the Judges' Houses stage of last year's X Factor.
Poole sang in front of Louis Walsh and Sinitta on that occasion, but failed to make it to the next stage, leaving her "heartbroken".
She claims that her performance then was the result of a "difficult year", saying: "Last year, myself and my husband had been through IVF and it had failed, then my marriage was in tatters, I had lost him and I had lost the hope of a family and I had lost the hope of a career singing... I came away from that feeling like that was it, I'm never going to do it again, I'm never going to sing again.
"But actually, no, that's not it. I didn't show you what I could do, you didn't see the real me then, so I'm back and I need to show you that, I want this more than anything, it means the world to me, I was put here to sing."
After a rendition of 'Clown' by Emeli Sandé, broadcast on tonight's (September 16) episode of The X Factor, the judges' all commented on the noticeable change in Poole's performance and demeanor.
Walsh remarked: "You're looking better and you're sounding better," while Tulisa Contostavlos agreed, saying: "Whatever Louis thought was missing, I think this year, you've got it."
Mel B described her performance as "absolutely incredible", and Gary Barlow added: "I think you are the dark horse of the competition right now, I really do."
Poole, in an emotional post-audition interview, said: "I feel so immensely happy and like I want to cry my eyes out at the same time, it's such a weird feeling. This is my shot and I am taking it, grabbing it and going for it."
The X Factor continues tonight at 8pm on ITV1.