On Saturday, viewers saw the 17-year-old struggle to perform for Cheryl Cole and Will.i.am because she had a sore throat and inflammed tonsils.
But the Girls Aloud star, 27, has given Cher another chance and picked her for her final 3.
Cheryl will also mentor Rebecca Ferguson and Katie Waissel.
Dannii Minogue, 38, has picked Aiden Grimshaw, Nicolo Festa and Matt Cardle in the boys category.
John Adeleye, Mary Byrne and Storm Lee will be mentored by Louis Walsh.
Simon Cowell's groups are 1 Direction, FYD and Bell Amie.
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