So it is the Big Mac's birthday, but here is how you can get a free sandwich.

On Thursday McDonalds will be launching its most recent innovation:  The MacCoin.  This universal 'food currency' is going to be handed out to honor the Big Mac's 50th birthday, and it can be used in 50 different countries to score a free Big Mac.

Starting at lunchtime on Thursday, customers who purchase a Big Mac will receive a free MacCoin at participating locations in the U.S.

There will be five different MacCoins, with each  representing the last five decades of the burger. The first will be decorated with flowers to represent the period of 'flower power' in the years it was first invented.

But there is no need to worry about missing the chance to snag a MacCoin on Thursday.  The fast food giant is still offering $1.00 Big Mac's on its mobile app through the end of September.

Eat up and enjoy!