Guinness has won the hearts of many—perhaps a little more than its maker, Diageo, planned for during the peak festive season. 

The widely loved Irish stout has recently seen a surge in sales, helped by its popularity among different demographics for its high quality and deep cultural roots. It’s become a drink of all seasons for more people than ever before. 

However, that unprecedented demand is forcing Diageo to put a lid on Guinness supplies in its home country just ahead of the festive season. 

“Over the past month we have seen exceptional consumer demand for Guinness in Great Britain. We have maximised supply and we are working proactively with our customers to manage the distribution to trade as efficiently as possible,” a Diageo spokesperson said. 

Guinness has a popularity problem that Diageo is still figuring out. The stout’s sales have defied beer market trends by growing while the industry shrinks. It’s captured new drinkers, become hugely popular thousands of miles away from home, and become an object of social media fascination. Guinness has found fans like Kim Kardashian, The Princess of Wales, and Jason Momoa, too.  

Americans have bought into “splitting the G,” making it the fastest-growing imported beer, according to Nielsen data cited by The New York Times.  

The rave reviews aren’t just for Guinness in its original form but also for its non-alcoholic version. Sales for Guinness 0.0 doubled during Diageo’s last financial year in Europe, making it a fast-growing segment of the outperforming beer category. 

These are all good problems to have independently. But together, they’ve left Diageo with a short supply of Guinness at a busy time of year. The London-headquartered company will impose a weekly cap on the stout’s supplies, reports suggest, while it copes with soaring demand. 

Diageo declined to comment on how long the cap will be in place.

Meanwhile, pubs in the U.K. are fretting about possibly running low on Guinness right when they need it. Some operators are supposedly “panic buying” ahead of the season, while others are bracing for a tight supply, according to The Times. As a result, Guinness lovers might have to watch their tipple during the festive season. 

While Guinness’s popularity is skyrocketing, problems with its supply may not last forever. Diageo has invested in new projects, including a €200 million brewery in Kildare, Ireland, and €25 million in new tanks to expand capacity for Guinness and its non-alcoholic alternative.

This story was originally featured on Fortune.com