Some McDonald's will now sell Krispy Kreme donuts

New York(CNN Business) McDonald's is adding a new menu item from an unusual source: One of its rivals.

Beginning October 26, nine locations in Louisville, Kentucky will start selling Krispy Kreme donuts as part of a test to "inform future menu decisions," both companies announced Tuesday. It's an unusual move since the two chains compete for breakfast customers and McDonald's has its own line of pastries as part of its McCafé lineup.

Krispy Kreme will deliver the donuts daily to the participating restaurants and customers can purchase them individually or in six packs. Available options include glazed, chocolate iced with sprinkles and raspberry filled.

"McDonald's is always looking for ways to give our fans more of what they crave, and we often conduct tests to inform future menu decisions," the chain said in a statement. "This small-scale test will help us understand how offering new bakery items like Krispy Kreme could impact operations in our restaurants."

McDonald's (MCD) said the test will run for a limited time. For the chain, it could attract new customers during the morning, where business has remained steady. Other parts of the day, including lunch and dinner, have declined in the midst of rising menu prices, according to research firm NDP Group.

The upside for Krispy Kreme is potentially bigger since it has fewer locations and wants to expand in the United States. The chain uses a hub-and-spoke model, meaning it makes donuts at its stores and bakeries and sells them at third-party locations such as convenience stores to help bolster its business.

Shares of Krispy Kreme rose more than 4% shortly after the partnership was announced.