The iconic Shamrock Shake from McDonald’s has returned for a limited time. But the shake isn’t the only thing that’s back: Grimace’s uncle, Uncle O’Grimacey, is visiting from Ireland to spread Shamrock cheer.

Together, Grimace and Uncle O’Grimacey are supporting Ronald McDonald House Charities (RMHC) and their mission to keep families together, celebrating the 50th anniversary of the first Shamrock Shake fundraiser. Starting Feb. 10, 25 cents from every Shamrock Shake sold at participating restaurants around the United States will support local RMHC families.

“Our fans eagerly await the Shamrock Shake each year. We are thrilled that proceeds from this minty-flavored treat will aid RMHC in keeping families together,” said Joy Silmon, second-generation McDonald’s franchisee, in a statement. “Family is a core value at McDonald’s, and we live this every day. Together, with our crew, customers and iconic McDonaldland character, Uncle O’Grimacey, we’re helping RMHC make families feel at home, even when they can’t be.”

The fundraiser runs through March 23 with a goal of raising $5 million, which could provide 50,000 overnight stays for families staying at RMHC programs, the company says. Fans can also don special Uncle O’Grimacey merchandise, including T-shirts, baseball caps and crewnecks. The swag is available for pre-sale at goldenarchesunlimited.com. In the spirit of the campaign, McDonald’s will donate to RMHC.

This latest Shamrock Season marks the next chapter of the Gift to RMHC celebration, the company notes, honoring the fundraiser that helped open the first Ronald McDonald House more than 50 years ago. McDonald’s and RMHS have partnered to “ensure that families can stay together during some of their most difficult times,” the company says. Since then, McDonald’s, its franchisees and its customers have collectively donated more than $1 billion to RMHC.

“Our long-standing tradition of the Shamrock Shake is a testament to the joy we bring our customers,” said Michael Gonda, chief impact officer of North America at McDonald’s, in a statement. “This year, we are getting back to the first fundraiser that started our incredible partnership with RMHC. This Shamrock Shake Season, with a little extra cheer from the Grimace family, we’re reminded that the most precious gift is being close to those you love.”