Modest fashion used to be something associated with certain religions. Not anymore.

Big name brands like DKNY, Dolce & Gabbana and Burberry have all begun to incorporate modest looks into their lines. And we’re not just talking about hijabs and headscarves. We’re talking about clothing with a longer lengths, a looser fit, long sleeves, lots of layering, basically looks that cover more skin and are fashionable at the same time.

Today, modesty is a booming business, expected to bring in $368 billion by 2021. So what’s behind this surge?

The Show spoke with Dimitri Koumbis, a professor in Rutgers’ Business of Fashion program for some insight.