Filming for Piers Morgan's Life Stories in the UK, The X Factor judge wept as she talked about splitting with footballer Ashley Cole over his alleged affairs.
The 27-year-old told Piers she still felt 'numb'. 'I was a heartbroken girl. Part of me will always love him,' she said.
But she would not confirm or deny that dancer Derek Hough is her new boyfriend.
The Girls Aloud member also sobbed as she talked about her near-death experience with malaria, triggering the audience to cry with her.
Diana Lyons, 26, who was at the show told The Sun, 'Everyone felt for her.'