The dynamic duo designed all the looks for their OK x I.T Blue Block collaboration, which incorporates colourful girly motifs – think blue skies and cotton-candy clouds – across a variety of products including accessories, swimwear, yukata and limited-edition pink crewneck T-shirts with embroidered peach-coloured Kiko logos. There's also a special showroom featuring OK bedding and decorations, with pyjamas, slippers and socks. The pop-up is a joyous fantasy world.

"I wanted to do the clouds because everywhere I go, I watch the sky," says Mizuhara. "It always makes me happy. When you're having a stressful day and you look up at the sky, you chill out and feel better. So for this very positive feeling and effect, I wanted the sky and also the idea of the rainbows – a sort of cute, happy element, with lots of flowers, butterflies, fruits and more. So designing wasn't that hard. I went through all the old Japanese magazines from the '90s and had a feeling about the patterns we wanted to go for."