Met Gala 2015: How the Stars Got Ready

— -- The Met Gala is just moments away, but the stars have been prepping all afternoon.

From Katie Holmes, who's experimenting with a new haircut, to Allison Williams, they're documenting it all on social media.

"Dare me..... " Holmes wrote next to a photo of a man holding a pair of scissors above her locks.

To see if she made the chop, fans will have to wait for the actress and her designer friend Zac Posen to walk the red carpet.

This year's event, which is to be held at the Metropolitan Museum of Art in New York City, is being chaired by Vogue's Anna Wintour, Jennifer Lawrence, Gong Li, Marissa Mayer and Wendi Murdoch. The theme is "China: Through the Looking Glass."

Though everything about the gala has been top secret, here's a glimpse into how a few A-listers are preparing.

Katie Holmes: "Dare me..... #metball @alternahaircare @olay @zac_posen @djquintero"

Allison Williams: "Starting off Met Ball prep with a Diet Coke that is literally the size of my face. #NotSponsored #JustAWeirdo #MetGala #LetsDoThis

Emma Roberts: "Doing my best not to wrinkle en route to #Metball @ralphlauren

Jaime King: "WAIT?!!!! HOW MANY STEPS DO I HAVE TO WALK UP PREGNANT IN HEELS?!!! Chinese Whispers is a full hot roller look right? Totally on point.... @matrix #matrix"

"Just hanging out with my mannequin! Can you believe they made a perfect form with my exact measurements with baby! #Met #Behindthescenes #whoknew?"

Kendall Jenner via Calvin Klein: "Countdown to #MetGala 2015. @kendalljenner stops in for a fitting with Women’s Creative Director @costafrancisco. Stay tuned for more exclusive coverage leading up to tonight's event. #calvinkleinlive"