Denim dresses are one of those wardrobe staples that will never go out of style. Remember when Britney Spears and Justin Timberlake showed up to the 2001 AMAs in head-to-toe denim looks? Spears' denim dress was a hot topic of discussion back then, and blue jean dresses are still getting major buzz 18 years later. The only difference is that the details have evolved a bit.