Singer and TV host Mel B went commando last Tuesday when she did the popular dance "Gangnam Style" in X Factor Australia.

In a skin-tight yellow mini-dress, Mel Brown attempted to do the Gangnam Style dance with their visiting guest star, South Korea singing sensation Psy. However, Guy Sebastian said it was something else that caught the attention of he and fellow judges Ronan Keating and Natalie Bassingthwaighte.

It is understood that Mel B went commando due to nature of her dress.

"People would have liked to have the view where we were in the judging panel - yes, it was 'scary'," Sebastian said with a wry smile yesterday, adding that the sheer dress gave away "a little bit too much information".

In 2009, Mel B revealed that she frequently went out without knickers.

"There are plenty of celebs around who seem to enjoy going out and about without any underwear on," she told Now.

"I don't have a problem with that - in fact, I'll often go commando to be a little risqué. But I'd never purposefully flash to photographers, that's just wrong! If I'm wearing a short skirt, I can assure you I'll always have my knickers on," the singer added.

She obviously forgot her number one rule on Tuesday.

Watch the video below to see how she dance the "Gangnam Style" as well as the weird reactions of the judges in the panel.