The fast-food chain’s most beloved milkshake, the Shamrock Shake, will make its grand return on February 21, McDonald’s announced. In addition to the Shamrock Shake, fans can also opt for the Oreo Shamrock McFlurry, which originally made its debut two years ago and is infused with crushed Oreo cookies. (Better yet, you can make a copycat recipe of the Shamrock Shake at home.) The minty-cool flavor mixed with vanilla soft-serve is a fan favorite, and now the chain has officially announced the widely-unknown “secret ingredient” that gives the milkshake its iconic green hue.  For years, people have flaunted Shamrock Shake-inspired manicures and fashion to reflect the popular color—and now we finally know the real deal. In a press release, McDonald’s revealed the hex color code of the signature shake: #cbf2ac.  RELATED: 8 Worst Fast-Food Burgers to Stay Away From Right Now. With this new announcement, mega-fans of the color can even go to their local hardware store and get paint mixed to the exact Shamrock Shake shade. “The only thing more refreshing than the delicious taste of a Shamrock Shake is the way that minty green hue makes the ‘will-winter-ever-end’ blues go away,” McDonald’s said. “In our 50+ years of serving up this tasty treat, we’ve never given away the secret ingredient that makes Shamrock Shake green so iconic. Until now.” In the release, McDonald’s also hinted that something else minty-green may be in the works. We’ll just have to wait and see what it is! “Starting February 21, our Shamrock green hex code just might unlock another tasty secret,” the chain added. “That is, if you know where to look. Be one of the first to figure out the mystery and you could get a little something special from us.“ae0fcc31ae342fd3a1346ebb1f342fcb For more milkshake news, check out This Is America’s Favorite Fast-Food Milkshake. This story written by Kristen Warfield has been reprinted with permission from Eat This, Not That!