Between walking numerous runways during Fashion Month and attending classes at NYU, model Karlie Kloss somehow squeezed in a serious hair makeover. And it's not just a basic switch-up — we're talking new length and new color. The 23-year-old posted a selfie on Instagram today showing off newly long — and blue — locks, complete with matching eyeliner. "Mermaid vibes on set," Kloss captioned the photo. As her pic implies, the new look appears to be for a photo shoot with L’Oréal Paris, so we're not holding our breath that her turquoise tresses will last past today — despite how good they look. Le sigh. Permanent or temporary, mermaid/unicorn/rainbow hair trended pretty hard a couple of years back, and it looks to be making a comeback — at least the blue-hue portion of ROYGBIV. Kesha dyed her mane an aquamarine color recently, and Kylie Jenner went icy blue — giving us déjà vu in the process. Three's a trend, after all. We've reached out to L’Oréal Paris for comment, and will update this post when we hear back.