Lindsay Lohan honors 'Mean Girls' day on Oct. 3

Mean Girls fans will never forget the day resident jock, Aaron Samuels, turned around in math class and asked Cady Heron what day it was.

In honor of one of the film's most quotable lines, Lindsay Lohan, who played Cady, took to Twitter on Saturday to celebrate Oct. 3, which mega-fans have long dubbed 'Mean Girls Day.'

PICS: The Best Quotes from 'Mean Girls'

"It's October 3rd FYI #meangirlsday," the 29-year-old actress captioned a nostalgic still from the beloved 2004 movie.

As Gretchen Wieners would say, Lohan's recognition of the faux holiday is "so fetch." Lohan followed it up with a screenshot of a WhatsApp text with her friend, Laura Slater, and according to these texts, the redhead was apparently confused of today's historical importance when she first woke up! WATCH: Lindsay Lohan Posts Super Confusing Caption on Instagram "Wow I do feel a bit late on this one haha," she wrote. "(Next step: #MEANMOMS) I'm trying to make it happen!"

How could Lohan ever forget this day? Other members of the cast, including Jonathan Bennett, who played Aaron, also took to social media to celebrate this very important holiday.

If these posts from Daniel Franzese (Damien) and Rajiv Surendra (Kevin) don't get you even more excited to celebrate, than we don't know what will.

If you're still in need of more Mean Girls, watch the video below to hear details about the time Lohan pitched her co-star and the movie's writer, Tina Fey, a housewives-themed sequel!