Samsung says the 7.3-inch "Infinity Flex Display" can be folded "hundreds of thousands of times" thanks to the display's thinness and flexibility. The device, which can be called Galaxy F or Galaxy Flex, will be presented next Wednesday 7 with two screens, one of 7.3-inch and another of 4.6-inch.
Samsung isn't the first to try foldable phones, but the company's display know-how, reach and marketing power could take the form mainstream. Although it has so far been mum on exactly when, analysts expect a launch date in the first half of 2019 - any later and Samsung would run the risk of new Apple phones stealing its thunder.
Google will be running sessions on how to support Foldables for developers during the Android Dev Summit this week, and we'll be looking at the new Samsung foldable shortly.
No word on availability, but mass production is set to start in the coming months.
The FlexPai smartphone is due to release soon in China.
The Korean vendor isn't the only vendor working on a foldable phone.
But across the industry, smartphone designs have been more about incremental improvements than bold new ideas - and consumers, unsurprisingly, have waited longer and longer to upgrade. Users now have the best of both worlds: a compact smartphone that unfolds to reveal a larger immersive display for multitasking and viewing content. They officially announced support for a category of Android devices it's chose to call "Foldables".
Screen technology has already been revealed that allows displays to be rolled with LG showing off its foldable TVs earlier this year.
In September, Samsung mobile boss DJ Koh said it was "time to deliver" a folding smartphone after the company had carried out market research which suggested there was a public appetite for such a device. It is a prototype device sporting the company's just-unveiled "Infinity Flex" flexible display technology.
Making matters slightly awkward, the move was announced as Samsung hosted its own developer conference in San Francisco.
In practice, operating system-level support for foldable screens means that altering an Android app to work with this type of device will be a relatively simple process for developers.