The 46-year-old Oscar-winning actress enlisted London-based colorist Nicola Clarke for the light rinse, reported E! online.
"We've been talking about doing it for a while but wanted to get all the award seasons out of the way to have a play and a bit of fun. It will last a couple of weeks, depending on how many washes it has," Clarke told The Telegraph.
Blanchett paired her new hairstyle with matching tinted aviator glasses, while out and about in London.
The "Carol" star joins a growing list of actresses who have sported pink hair, which includes the likes of Kaley Cuoco, Katy Perry, Rihanna and Helen Mirren.
