As Nigel Tufnel discovers in 'This Is Spinal Tap' when label execs rejected the band's cover for 'Smell the Glove,' there's a difference between sexy and sexist. Hair-metal revivalists Steel Panther recently learned the same lesson, as advertisements for their 'Balls Out' album have gotten them in trouble with U.K. regulators.

According to Blabbermouth.net, the Advertising Standards Agency (ASA) deemed the posters -- which, like the album cover, show a scantily clad woman dangling a pair of metal balls between her legs -- "likely to cause widespread offense" and "unsuitable to be seen by children." As such, they're "not appropriate for outdoor advertising" and cannot go back up in their current form.

The trouble started when a domestic-abuse group complained to the ASA, claiming the image was demeaning to women. In a reversal of Spinal Tap's situation, Steel Panther's label, Universal Island, came to the band's defense and said that the picture was meant to be "over the top" and therefore not taken seriously.

Check out the 'Balls Out' cover below:

Universal Music Group

Steel Panther's reps further insisted that the promo was only placed in bars, nightclubs and other places frequented by adults.

While the ASA ultimately agreed that the posters were not "meant to cause offense," they nevertheless deemed the image, as well as the album's title, too sexually suggestive for the general public.

It's scary how closely life imitates 'Tap.' Steel Panther's drummer had better watch out for spontaneous combustion.

Watch Steel Panther's ''Balls Out' Photo Shoot' Video