Ever wonder how McDonald’s Shamrock Shake came to be? Look no further than McDonald’s Archivist Mike Bullington for a speedy history lesson, joined by his besties: Grimace and Uncle O’Grimacey.

Your favorite McDonald’s green treat is even sweeter this year – from February 10 – March 23 at participating U.S. restaurants, 25 cents from every Shamrock Shake sold will be donated to Ronald McDonald House Charities (RMHC) and its network of local Chapters in celebration of our founding and forever partnership that started 50 years ago.