New York (CNN Business) Wendy's will start serving breakfast across the United States next year.

It's a big undertaking for the fast food company. Wendy's plans to hire about 20,000 US employees for the initiative, the company said Monday.

Currently, Wendy's offers breakfast, including a bacon sandwich and a honey butter chicken biscuit, at about 300 locations. The nationwide launch "provides incredible growth opportunities," said Todd Penegor, the company's president and CEO, in a statement.

Menu innovations have helped boost Wendy's sales . A number of new menu items — including a new $5 Giant Junior Bacon Cheeseburger, a new line of chicken sandwiches and a $5 meal deal called the Biggie Bag — helped boost first-quarter sales at North American stores open at least a year.

Breakfast may help drive growth, but it's a costly endeavor. The company expects to spend about $20 million to serve breakfast throughout the country, and is lowering its 2019 financial outlook. Shares fell 8% in premarket trading Tuesday.

, as well as strong demand for its breakfast sandwich value deals. For Dunkin', the efforts are paying off. The chain's sales at US stores open at least a year jumped 2.4% in the first quarter , thanks to higher-priced espressos and frozen drinksas well as strong demand for its breakfast sandwich value deals.

— CNN Business' Jordan Valinsky and David Goldman contributed to this report.