By proposing – through the pages of the New York Times and Chicago Tribune – a joint product, the aptly-named McWhopper, "one delicious, peace-loving burger", the brand sought to bury the hatchet to promote the United Nations-backed celebration.
And it was a great idea.
Why? Because it did all of the things that a successful stunt needs to do. First, it achieved heaps of coverage – in itself a good thing in the highly-competitive market of fast food.
Read more: Meet the McWhopper
Second, it was simple, unexpected and - crucially - funny. It made people laugh in a way that yet another advert showing a burger just doesn’t do.
And finally, it posed a tough question to their rivals – how to respond in an equally amusing manner.
In that regard, McDonald's completely mucked up. Their very po-faced response seemed laboured and lacking a sense of humour. It’s about burgers after all – you can afford to laugh at yourself, guys. McDonald's missed that obvious and crucial point.
Read more: Fast food chains beg to be a part of Burger King's epic mashup
If they had accepted the challenge, it would have gone better for them, but there would still be the sense that McDonald’s were being forced into a corner by a smarter competitor, with Burger King leading the way.
A tricky toss up, but I think that McDonald’s well and truly made the wrong call.
Critics of stunts say that they’re artificial and past their sell-by date. That people are bored of them. And that certainly can be the case.
But consider this. Bear in mind all of the money McDonald’s and Burger King spend on adverts. And then remember how much favourable publicity this stunt generated. The cost? Somebody’s time bashing out a letter and following it up with some tweets.
That’s a fantastic return on investment – PR at its best in many ways.
The crucial point in its success was the fact that it was tied to the International Day of Peace and that the proceeds were to be donated to Peace One Day, a not-for-profit. By doing so, Burger King had the perfect excuse for carrying out what might normally have been viewed as a mean-spirited stunt.
So, for now, Burger King 1 – McDonalds 0.