But is it just a wig?!
The actress dazzled on the red carpet in this teal, glittered gown complete with a cone style skirt and floral detail, but it was her hair that really stole the show.
Rocking the Zac Posen number, Katie shunned her luscious long locks for a blunt bob with a choppy fringe, channelling editor-in-chief of Vogue and host of the Gala, Anna Wintour, with the brunette hair piece - and we've got to say - the edgy look suits her!
Katie even took to Instagram to pretend that she had braved the scissors as she posed with hairdresser-to-the-stars and good friend, DJ Quintero, who is pictured holding up her super long tresses and preparing to give them a chop!
Nothing gets past us, Katie.
The star captioned another snap with "Dare me" as she visited the salon to undergo the red carpet transformation, which shows the salon professional getting dangerously close to her hair...
Katie joined the likes of Kendall Jenner, Rihanna and Sarah Jessica Parker at the star studded bash in New York yesterday evening wearing the wig that was reminiscent of the choppy style she rocked when daughter Suri was a toddler.
The edgy style put her firmly on the map as one of America's most stylish actresses.
We might just re-think that trim next time we visit the hairdressers. Thanks for the inspo, Katie!
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Met Gala looks below:
Copyright: Rabbani and Solimene Photography/Getty Images