A pint glass that reveals a QR code when filled up with Guinness has been unveiled by the iconic brewery.

Designed by BBDO New York, once topped up, the black stout liquid fills out the code that has been crafted into the glass container. The QR code can then be scanned with a mobile device, which will in turn unlock content. 

This can be in the form of downloadable coupons, promotions and other exclusive Guinness news and merchandise, while the code will also tweet what you’re doing, update your Facebook status and check you in via Foursquare.

It’s a novel way of letting your friends know you’re enjoying a pint of the black stuff and scanning the code will even invite them down to join you. 

The specially designed QR code pint glasses only work with Guinness, so there’s no point in trying it with any of your lagers or bitters. 

Of course if you’re after a crafty pint after work before going home to the wife and kids, you might want to refrain from giving the game away by opting for a more traditional glass.

What do you make of the novelty QR code Guinness glass? Thought are more than welcome.