But gazing into 2019, the stars are veering from jewel tones and leaning into pastel hues. For example, sapphire was hot last summer , but now the top shade lighting up the heads of Hollywood is a powdery blue. Lady Gaga and Kylie Jenner are both rocking icy blue hair to start the new year — and you can get it, too. We talked to the celebrity colorists behind the sky blue trend to get tips on how to copy the look at home.