According to the Daily Star, a member of the crew incorrectly introduced the 37-year-old singer to the audience as her bandmate, before hurriedly correcting himself.
Mel B has been drafted in as the fourth judge for the Manchester leg of auditions, with producers still yet to find a full-time replacement for Kelly Rowland (who confirmed she was leaving the show in April).
Gary Barlow is said to be keen for Mel B to join him and fellow X Factor judges Tulisa and Louis Walsh on a permanent basis. The Leeds-born popstar, who sat on the Australian X Factor panel last year, previously said that she was looking forward to being part of the show.
"I'm so, so, so excited to be a guest judge in Manchester. Being a Northern girl, I believe there's lots of amazing talent in the North of England. I am coming to find the winner.
"I love my job as a judge on The X Factor Australia," she added. "But it will be great to sit on the panel in the UK. Britain is, and always will be, my home and first love."
