As bland as they may be, those brown shipping boxes that often find their way to our doorsteps are unmistakably Amazon. Soon, however, they may be a thing of the past as the ecommerce giant for the first time is allowing third-parties to advertise on its boxes.

If you've ordered something from Amazon recently, your item may have arrived in the bright yellow boxes shown above. Amazon has been shipping products in these limited edition boxes for the past week which feature characters from the upcoming Minions film that'll hit theaters July 10.

There are three different Minion box sizes, each with a different character emblazoned on the side.

For those unfamiliar, Minions are the yellow characters from the Despicable Me franchise. Films under the banner have already grossed more than $1.5 billion at the box office, leading to a wealth of Minion-laden merchandise.

Amazon partnered with Universal Pictures and Illumination Entertainment on the effort. It's unclear whether or not the boxes are being sent to all customers or if Amazon is targeting select shoppers (perhaps those that have ordered kids toys, for example). My bet would be the latter but that's just pure speculation on my part.

This particular campaign aside, Amazon may have stumbled onto a serious revenue generator here. Given the company's razor thin margins, any extra revenue would be welcomed among investors. And who knows, maybe we'll see UPS, FedEx or the US postal service follow suit.