Lucy Spraggan quit The X Factor 2012 on Saturday morning, citing her continuing illness.
The 21-year-old said in a statement: "I am gutted not to be able to continue on this journey but I'm not well enough to perform. To accept another free pass having missed last weekend would not be fair on the others in the competition.
"I wish them all well. I would like to express my thanks to everyone who has supported me. There is no way that this setback will prevent me from fulfilling my ambition.
"You'll be hearing from me again very soon."
Breaking a week long Twitter silence today, Lucy tweeted her followers: “A massive thank you for all the support throughout the show, you’ve been incredible. I can’t wait to perform again. #thankyou”
Speaking on the Xtra Factor during the weekend, Tulisa said she was hoping to continue to mentor Lucy despite her exit.
“I hope I can continue to mentor her in the future," the 'Young' hitmaker said. “I now count her as a friend as she is an amazing girl.”
Meanwhile a source from the telly show revealed: “Lucy has a massive fan base from her time on the show, and with Tulisa’s help the world is her oyster.
“Tulisa is still selling records and topping the charts, so she will be able to help Lucy make it as a pop star.”
The X Factor continues with its live shows next weekend with a Best Of British theme.
Sunday's results show will feature performances from One Direction and Little Mix, as well as one more act being given the boot.