The color: blue-gray
Celebrity inspiration: Irene Kim
Description: "A look like this will most likely require a two-process, depending on how light the hair is to begin with," said Eliut Rivera, a celebrity stylist whose clients include Penélope Cruz, Naomi Campbell, and Sheryl Crow. "While it is up to the colorist to get the right blue, this one seems to have gray in it, as well. You can start with coloring the whole head and wait for it to grow out a bit, or start a little from the roots. With this look, keep the ends lighter than the roots by adding more gray at the end."
Who it works for: A general rule of thumb is to stick to pastel tones if you're lighter and deeper hues if you're darker. This color falls somewhere in between, so as long as you've got the confidence to rock it, go for it! Plus, all our colorists agreed: the rules pretty much go out the window when we're talking about bold rainbow hues like Irene's blue-gray.