The former Signed by Katie Price contestant was seen being put through to Judges Houses' on Sunday's episode (September 23) over fan favourites Joseph Whelan and Joe Cox.
Responding to the outrage that followed his Boot Camp success, Clark wrote on Twitter: "I've ben told not to react to all the s**t on here but I'm sorry, I'm a mouthy bastard so I'm gonna.
"I've EARNED my place at judges houses just like every other person in this comp, not everyone is going to like me, I know that, but don't judge me for doing something I've always wanted to do.
"For those who are supportive thank you so much, it means the world. For those that ain't.. Go and have a w**k."
Clark's X Factor mentor Nicole Scherzinger recently defended the ex-boyband member, saying he "would definitely have his own audience".
Speaking to Digital Spy yesterday (September 24), Clark's fellow contestant Jake Quickenden described him as "the best lad ever" and insisted that he "totally deserves to be there".
Watch Digital Spy chat with The X Factor's Jake Quickenden below: