Krispy Kreme is adding a chocolate version of its famous glazed doughnut to the menu - but there's a catch

Krispy Kreme is adding a new doughnut to the menu - but only for three days. 

On Wednesday, the doughnut chain announced that it would debut the first-ever chocolate version of the chain's iconic original glazed doughnut to celebrate the solar eclipse.

The doughnut will launch on Monday, August 21, the same day as the solar eclipse. However, customers can purchase the limited-time offering prior to its official debut during evening Hot Light hours on August 19 and 20. 

The doughnut will be made by covering the classic original glazed doughnut in a chocolate glaze. 

Here's an ad showing the chocolate glaze waterfalls in action: 

"The solar eclipse is a rare occasion providing a total sensory experience for viewers across the continental U.S." said Jackie Woodward, Krispy Kreme Doughnuts' CMO, said in a statement. "Chocolate will have the same effect as we introduce a first-time chocolate glazing of our iconic Original Glazed Doughnut." 

August 21 will be the first time in 99 years that a solar eclipse has crossed the U.S. from coast-to-coast.