Joining co-stars Zooey Deschanel, James Corden and Justin Timberlake at the Regency Village Theater in Westwood, California, Anna went all-out '80s with her hair – and looked fabulous!
Anna chose a stunning, jewel-encrusted velvet Marc Jacobs dress for Sunday's premiere (23 October), wearing it with black, sky-high strappy heels and what, on first look, seemed to be a simple, low ponytail.
It wasn't until she turned around and we saw the back of the Pitch Perfect actress' head, that we realised her updo was anything but simple!
Anna's ponytail was actually randomly crimped, '80s style, from about an inch from her roots, all the way down to the ends.
Pretty cool, huh?
To copy her look, part your hair in the middle and, working on dry hair, crimp one-inch sections using the BaByliss Pro Crimper, £19.99, superdrug.com.
You could even try spritzing each section with a heat-protective fixing spray beforehand to add extra definition and hold. We love VO5 Smoothly Does It Tame and Shine Spray, £4.99, boots.com.
When you've crimped 10-12 sections, gently scoop all of your hair into a low ponytail and fix with a covered band. Take a small section of hair from underneath the ponytail, wrap it around the band and fix with grips to finish.
Crimping has become more and more popular on the red carpet this year with everyone from Ariana Grande to Bella Thorne rocking the look in various guises.
What's next we wonder, scrunchies and Alice bands? Ooh, we do hope so!
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