Will You Be Lovin' All-Day Breakfast?

Well, you can sleep in and not miss McDonald’s breakfast items, that is. There are no guarantees your boss will be cool with you sauntering into the office after noon, Egg McMuffin and hash browns in hand.

The much ballyhooed all-day breakfast debuts nationwide Tuesday with most of the menu items available. Hotcakes, sausages, burritos, parfaits and hash browns will be served up, along with the famous Egg McMuffin. McDonald’s has staged a hyper rollout of advertising from multiple agencies, along with digital elements including GIFs, Snapchat filters and a Twitter relay, as it prepares for the big launch.

McDonald's hopes to boost sagging sales and take on breakfast upstarts like Subway, Panera and Taco Bell that are challenging the fast-food giant for breakfast supremacy. The franchise company began testing the all-day breakfast menu in March.

Same-store sales at McDonald’s roughly 14,000 restaurants in the U.S. have fallen over the last five years. In the first quarter of this year, revenue fell 11 percent from a year earlier, to $5.96 billion. Earnings per share dropped 31 percent from the previous year. Overseas, McDonald’s has suffered from supply issues and a food safety scare that swept Asia.