As far as red carpet mainstays go, Zac Posen is really down to incorporate high-tech elements into his craft (more so than many of his designer peers). Coco Rocha closed his ZAC Zac Posen spring '16 in a LED dress programmed by teen coders, after all. We expected big, innovative things from Posen given this year's Met Gala theme — and he didn't disappoint.Posen's contribution to this year's "tech white tie" dress code was an illuminating ball gown, which he teased on Instagram earlier in the evening. He conveniently obscured the wearer's identity by instead showing off the garment's glowing attributes. When the designer rolled up to the Met, it was Claire Danes on his arm in the magically lit gown.The glow-in-the-dark effect comes from the fiber-optic woven organza, the brand shared on Twitter . On the red carpet, the dress didn't technically light up. Instead, the powder-blue hue felt more Disney princess than sci-fi. (There were Cinderella comparisons , naturally.) The ultra-classic silhouette was straight-up stunning. However, the elegant gown was most impressive in total darkness — not quite the lighting scheme on photographer-clogged step-and-repeats. But there's video evidence, courtesy of Posen's Instagram.