Britney Spears is getting jiggy ...and wiggy with it!

The sexy pop star, rockin' a black bob wig and sexy halter top, is showing off her lean body in these behind-the-scenes pics from the Fantasy Twist campaign ... Brit's latest fragrance combo containing her best-selling scents, Fantasy and Midnight Fantasy.

The X Factor judge definitely knows how to capture our attention. For a perfume campaign, nothing about this photo shoot stinks!

Click thru to see Britney's finished ad.