The X Factor finalists have spoken of their delight at the success of their charity single, which looks set to reach number one.
The four remaining acts - Misha B, Little Mix, Amelia Lily and Marcus Collins - were talking as they played a secret gig in central London.
The finalists have collaborated on a cover version of Wishing On A Star to raise money for Together For Short Lives, which provides support for children unlikely to reach adulthood, as well as their families.
The single also features the other finalists on the ITV1 show, along with previous contestants JLS and One Direction.
The release has been outselling its nearest competitor Olly Murs' Dance With Me Tonight this week by more than two copies to one, according to the Official Charts Company.
Speaking ahead of their performance, Jesy Nelson of four piece Little Mix, said:
"It would be amazing if we got to number one. It would be an overwhelming feeling knowing that we're helping so many kids."
Soul singer Misha B, who has been mentored on the show by Kelly Rowland, said she was also thrilled that the single was selling so well.
Photo: © Rex