McDonald’s customers can soon pair Krispy Kreme donuts with their morning McCafe, in a new food partnership that seeks to expand both brands but that could wind up weakening them instead.

Three types of Krispy Kreme donuts — original glazed, chocolate iced with sprinkles and chocolate iced “kreme” filled — will go on sale at McDonald’s restaurants starting later this year, the companies told CNN on Monday.

Krispy Kreme shares jumped roughly 18% on Tuesday morning. McDonald’s shares lost 0.2%.

It’s not the first time two competitors have teamed up. For example, Wendy’s brought in Cinnabon to its breakfast lineup earlier this year. Some research suggests brand partnerships open possibilities for new customers, brand expansions and innovation. But some retail experts suggest partnerships can also be a risky move, and one that can put off McDonald’s franchise owners, create communication hurdles and weaken the respective brand names.

McDonald’s has also faced pushback from customers as prices on its other menu items rise. Ian Borden, McDonald’s chief financial officer, said earlier this month that some lower-income Americans are opting to cook at home instead of dining at its restaurants. In February, CEO Chris Kempczinski addressed McDonald’s “affordability” problem and indicated the chain would cut prices on some menu items.

Krispy Kreme is giving away a free glazed donut to guests who visit a Krispy Kreme location between 5 and 9 pm on Tuesday to celebrate the partnership.

The addition of a Krispy Kreme donut to the McDonald’s customer’s breakfast order began as a test at 160 restaurants in Kentucky. The donuts will be available nationwide at participating restaurants by the end of 2026, after a phased rollout beginning later this year.

The donut will be available to purchase individually or in a pack of 6, starting at breakfast, and will continue selling until they run out.

There are far fewer Krispy Kreme locations than McDonald’s, which had almost 13,500 US locations in 2022. But customers can buy Krispy Kreme donuts in other places, such as Walmart and other grocery stores. The partnership could increase the scope of Krispy Kreme, which said it has been scaling its supply chain to keep up with its promise to deliver fresh daily.

“By making Kreme Krispy (sic) accessible to fans nationwide through this partnership, we expect to more than double our points of access by the end of 2026,” said Krispy Kreme President and CEO Josh Charlesworth in a statement.