During the auditions, it seemed the pair were the best of friends, but when the pressures of the live shows arrived and the competition grew fiercer the pair were invovled in several bitter rows.
Kelly said Tulisa was making her life a "living hell" and a week after Tulisa branded one of Kelly's acts a bully, Kelly pulled out of the show for a week claiming illness.
Afterwards, the couple put on smiling faces for the cameras but according to reports, behind the scenes they barely spoke to each other.