Wendy's rolls out breakfast menu on McDonald's National Egg McMuffin Day

Are McDonald's and Wendy's in the middle of a breakfast war?

On Monday until 10:30 a.m., you can get a free Egg McMuffin sandwich if you have the McDonald's app on what the chain is calling National Egg McMuffin Day.

The sandwiches have been around since 1971, so McDonald's says it's celebrating the 50 year anniversary a year early.

But Wendy's may be trying to rain on the Golden Arches' parade.

Wendy's rolled out its own breakfast lineup Monday, which includes the Breakfast Baconator, Frosty-ccino and Honey Butter Chicken Biscuit.

But leading up to the free Egg McMuffins deal, Wendy's was talking smack on Twitter, going so far as to tweet an image of a headstone with the words "RIP Egg McMuffin" and the words "Here lies mediocrity."

Wendy's continued the battle in its Twitter replies to customers.

"McDonald's is giving away free Egg McMuffins," one person wrote.

"Oh cool, free disappointment," Wendy's snapped.

Wendy's has breakfast coupons available on its app as well, which includes getting a free Honey Butter Chicken Biscuit. But you'll need to make a purchase.

Wendy's also claims under its "America's Favorite Breakfast Guarantee" that, if you don't love something they make you, they'll exchange it for free.