But now - finally! - it's easy to steal her look. The man responsible for her blonde, celebrity hair stylist Harry Josh, has shared the secret to her colour on Instagram, Harper's Bazaar UK uncovered, and it's surprisingly simple.
"It's only highlights with 20 volume bleach - which she does 2 or 3 times a year, if I'm lucky! She’s so low maintenance! There is no base break, etc," Josh captioned the below pic.
This article previously appeared on marie claire.