While attending the Wimbledon men's singles finals with husband, Prince William, Kate wore a custom made dress by New Zealand-born, London-based designer Emilia Wickstead.
On the exact same day in the Bahamas, 21-year-old Kylie posted two photos of herself wearing a baby blue Jacquemus dress, matching with her BFF Stassie.
Interestingly, both Kylie and Kate's blue dresses were textured: Kylie's a ribbed material and Kate's an elegant crepe.
Given that baby blue has now had the tick of approval from both British and American royalty, we'd say the colour is about to overtake green as the most on-trend hue of the Northern Hemisphere's summer.
Shop the colour below.
Phillip Lim, Cropped cold-shoulder cotton-poplin top, $168, Netaporter.com
Khaite, Clarice stretch-knit turtleneck sweater, $555, Netaporter.com
Zulu & Zephyr, Signature one-piece in powder blue, $160, Zuluandzephyr.com
Cult Gaia, Claire gathered-panel top, $508, Matchesfashion.com
Mango, Cotton shirt dress, $99, Mango.com.au