Enjoy a free smoothie on National Flip Flop Day

Friday, June 14 is National Flip Flop Day, so put your best foot forward!

Americans wear flip flops just about anywhere, from the beach and playground, to the streets and even on the red carpet.

To celebrate the day, Tropical Smoothie Cafe is treating its customers to a free 16-ounce sunshine smoothie.

All you have to do is wear your favorite pair of flip flops to score the treat. No purchase is necessary.

The offer runs from 2 p.m.- 7 p.m. at participating locations in more than 40 states.