Get your calendars ready, tomorrow (Thursday, May 28 ) has been declared "Burberry Day" by New York City's Mayor Michael Bloomberg. (Yes, you still have to work and no, you don't have to wear plaid!) The New York skyline is about to be changed forever -- check out the time lapse video of the Burberry sign above to get your own countdown started!

In addition to opening its new Madison Avenue headquarters, the brand intends to use its new Burberry Foundation to contribute half a million dollars to local youth projects that help kids realize their potential through creative outlets.

Additionally, according to WWD, our favorite British purveyor of plaid will announce plans to double its NYC retail presence. If all of that isn't reason to break out the good champers, we don't know what is.

Of course, we're not the only ones who think a party is in order. Tomorrow evening, a 50-foot-long Burberry logo at the top of the brand's building will light up, while the 54th floor of the Palace Hotel will serve as the location of a super stylish soiree for 300 fashionable guests.

Celebrities from both the States and across the pond will be in attendance, including the Olsen twins, Blake Lively, Peaches Geldof, Sean Lennon, Helena Christensen, Nicky Hilton and more.

So what does the American Burberry HQ look like? According to WWD, it takes up 68,000 square feet, four floors and, like the London headquarters, was designed by creative director Christopher Bailey, who chose a neutral palette of gray, black, and chocolate brown. Common areas feature LED screens to, most importantly, watch runway shows.

Two 1500-square-foot concept stores will be at the Madison Avenue address -- currently, both spaces are empty, but not for long. One will house Burberry London and the other, the brand's recently updated Burberry Brit, which will arrive in November.

Ready to start shopping? Thursday is the day to do it -- 20 percent of all proceeds made at the 57th Street and Spring Street (SoHo) locations will be donated to the Burberry Foundation, so you can buy your designer goods guilt-free!