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."
Watch presenter Dermot O'Leary talk to Digital Spy about the 2012 series of The X Factor below: