Nintendo has filed a patent for a smartphone case that effective turns your handset into a working GameBoy.

This could also means it will release GameBoy games onto Apple and Android app stores as a treat for retro games fans.

The case design, which was filed with the US Patent and Trademarks Office in March this year and published at the end of September, has a 4:3 hole for the screen and all the correct buttons found on the 80's handheld console.

It clearly works by pressing capacitive sensors onto the smartphone screen that an app recognises and responds with actions on its smaller playing display. It's a simple concept that we've seen in action before, on toys that turn phones into miniature arcade cabinets, such as the iAppCade we saw in 2012.

The beauty of Nintendo's design is the case can also be used for protecting the phone too, so you don't have to remove it to use the handset properly.

Its not the first time we've seen a phone turned into a GameBoy. FunStock Retro stocks the Hyperkin Smart Boy, which works with Android devices and is currently on sale for just £19.99.

However, rather than work with games installed on a handset - as we believe Nintendo plans to introduce - the Smart Boy works with existing GameBoy cartridges, which slot into the back of the device.

There is no time scale for Nintendo's GameBoy case to hit stores or even confirmation that the patented design will ever come to fruition. We'll keep you up to date if we hear more though.