A spokesperson for the show said tonight: "We've not heard from her, and we don't know if she's going to be back."
The feisty 55-year-old wife of former Black Sabbath star Ozzie Osbourne announced live on air during last night's results show: "I'm out - gone!"
Show host Dermot O'Leary told viewers: "Sharon can't choose between her acts. The final vote will be between three judges, as Sharon has decided to leave."
A mutinous Sharon Osbourne is flanked by the rest of the X factor judges. She walked off last night's show life on air screaming 'I'm out - gone'
Kimberley Southwick, 19, was thrown off the ITV1 programme by the judges after poor viewers votes left her facing eviction, alongside fellow under-25 contestant Alisha Bennett.
Sharon refused to take part in the eviction process, leaving Louis Walsh to send Kimberley home after her performance of It's Raining Men received a mixed response.
Earlier in the show, after Alisha's poor performance Sharon pleaded: "Get rid of me, not her."
Yet contestant Kimberley claimed "We knew it would be us in the bottom two and Sharon knew it too,"
She added that Sharon had been "great", but admitted she felt hurt that she was not more supportive during the live programme.
Swan song: Kimberley Southwick belts out 'It's Raining Men' which failed to impress the judges
"I understand why she's so upset, but you know, I would have liked her to have held my hand a bit longer, and stayed on stage with us," she said.
"I think she just took it as a personal thing that it was me and Alisha in the bottom two."
Kimberley said she was unsure whether Sharon still planned to leave the X Factor, adding: "She did quit on air, but I haven't spoken to her this morning. end
X Factor bosses are now in crisis talks after Shazza told the show's host, Dermot O'Leary: "What I did was no good—and I think I'm going home now, Dermot."
A show insider said: "At this point in time Sharon has said she is no longer a judge on The X Factor. We are hoping she will be able to sleep on her decision and calm down.
"The public rejected two of her acts and she took it as a hammer blow. She also blames herself for picking both girls the wrong songs."
The judges take to the stage. This year's series has been plagued by feuds and controversy
Radio 1 breakfast host Chris Moyles is allegedly being lined up as a replacement should Sharon finally decide to quit.
A source added: "Chris Moyles has made it clear he's on standby if Sharon or Louis Walsh walk out at short notice. Simon Cowell is likely to take him up on that offer."
This year's series of the X factor has been plagued by feuds and controversy. Louis Walsh has been sacked and rehired and rumours have been rife over Sharon's reported jealousy of sexy judge Dannii Minogue.
Meanwhile loser Kimberley will return to work in the pub owned by her parents.
The 19-year-old recently quit a call centre job because she found it 'boring'.
