In celebration of National Donut Day, Tim Hortons Cafe & Bake Shop is offering its US Facebook fans and those who newly "like" its US Facebook page a free donut with any purchase coupon valid on June 1.

This is the third year the cafe bakery chain has participated in National Donut Day celebrations with an online coupon.

"Our beloved donuts are a significant part of the foundation of this company," says Mike Meilleur, senior vice president of US operations, Tim Hortons. "We think National Donut Day is as much of a holiday to celebrate big as any other national holiday. The Facebook coupon is our way to reward our loyal guests and introduce new fans to the brand."

The first Tim Hortons restaurants offered only two products—coffee and donuts. The selection of donuts to enjoy was highlighted by two original Tim Hortons creations, the Apple Fritter and the Dutchie. Still known and loved today for its wide variety of trademark donuts and bite-sized Timbits, the chain's bestselling donut in the United States is the Boston Cream.

National Donut Day is celebrated across the United States on the first Friday in June. The annual event originated in 1938 as a Great Depression fundraiser by the Chicago Salvation Army to honor women who served donuts to soldiers in World War I.