McDonald's is giving away free coffee to its customers for a limited time as competition for the breakfast crowd intensifies.

The world's biggest hamburger chain announced Friday that participating U.S. locations will offer free small McCafe coffees during breakfast hours from March 31 through April 13.

The announcement comes as Taco Bell rolls out ads to promote its new breakfast menu, which includes a waffle taco. The ads star everyday men that happen to be named Ronald McDonald.

Chains like McDonald's, Taco Bell and Starbucks, which recently revamped its sandwiches, are all fighting for a piece of the breakfast market because people are increasingly buying breakfast on the go.

McDonald's Corp.'s McCafe product line, which also includes iced coffees and other drinks, debuted in the U.S. in 2009.