Michelle Williams has ''regular clean-ups'' to help grow out her signature pixie haircut.

The 38-year-old actress is known for her platinum blonde cropped locks, and according to celebrity hairstylist Kristin Heitkotter - whose clients include Busy Philipps, Reese Witherspoon, Kiernan Shipka and Molly Sims - Michelle has maintained her long layers in order to cut her hair into a ''short bob'' style.

Kristin said: I've always been a big supporter of hair change. And if it feels right for you, I say go for it. Have an in-depth consultation with your stylist to make tweaks suited specifically for you. There are so many variations that short hair can be right for many face shapes and hair textures.

''I think it's important to have regular clean-ups during the growing-out process, to maintain some shape/style. Start growing most layers longer by just mainly trimming the bottom until you can cut your hair into a short bob...and then continue growing out from that point. Or for a more shagged style, just grow all the layers out evenly and maybe rock it with a shorter bang.''

The A-list hair guru swears by L'Oreal's famous Elnett hairspray to keep any flyaway hairs in place, and also used a temporary tint on Busy's tresses to help her achieve a chalky pink hue.

She told E! news: ''Elnett Hairspray has been a staple in my kit for as long as I can remember. Great working hairspray.

''Busy's go-to for her pink hair vibe is Kristin Ess Rose Gold Temporary Tint. This spray in tint is so easy to apply and fades out evenly and gradually.''