X Factor finalist Emily Nakanda has left the show after an online video showed her attacking a girl.
In the clip, Emily, wearing a school uniform, is seen pulling another girl's hair and holding her around the neck.
Emily, 15, is the youngest contestant ever to get to the final of the show. The lower age limit for X Factor was reduced for this series.
Judge Sharon Osbourne, who mentored Emily, said: "I am deeply saddened by this whole situation."
A statement on the ITV website from Emily's mum says: "As a family we are heartbroken and are very disappointed with Emily's behaviour.
"We feel that there is no choice but to withdraw Emily from the competition.
"Emily regrets her actions but there is no way, as a family, we can excuse her behaviour.
"Emily is very sorry to have let the show, Sharon and the viewers down."
The people running the show for ITV have said even though Emily has left the show another act will still be voted off on Saturday.