Samsung's highly anticipated foldable-screen phone, known as the Galaxy X or maybe Galaxy F, has finally been teased at a developer conference.

Although Samsung's foldable phone is a little way off yet, the firm has teased it for the first time at a developer conference, although it was shown off with the lights dimmed to hide the design. Unveiling the Infinity Flex Display, Samsung said it has "paved the way for a breakthrough foldable smartphone form factor."

Now it's been shown in the flesh, we know that the foldable phone will have a tablet sized screen that can be folded in half to fit in a pocket. The 7.3in main display with use Samsung's new One UI and be able to run three apps at the same time.

"The app experience seamlessly transitions from the smaller display to the larger display as the device unfolds. In addition, users can browse, watch, connect and multitask without losing a beat, simultaneously using three active apps on the larger display," said Samsung.

Samsung Galaxy X foldable phone

When is the Samsung Galaxy X/F release date?

The wait for the Galaxy X foldable phone goes on as although it was possible it would be announced on 11 October at Samsung's 4X event, this turned out to be for the Galaxy A9 with is four cameras.

It seems the device is likely to launch in 2019 with Samsung stating it will start mass production of the Infinity Flex Display in a “matter of months”, according to The Verge. So it's possible we could see a proper announcement at CES in January.

However, a report by Yonhap News Agency in South Korea suggests the phone will be unveiled fully in March 2019, not long after the Galaxy S10 which should arrive in February.

The Galaxy X has already passed certification and there was an oops moment when it recently popped up on Samsung's support site, suggesting it is nearing completion.

The bad news is that Samsung’s quirky folding phone might be tough to bag, with Forbes stating that “the expectation for the Galaxy X is as a limited-run device in a single territory - more than likely the home territory of South Korea”.

What is the Galaxy X/F price?

If rumours on the Galaxy X pricing are true, we have no trouble believing it will be a rare handset. Samsung's foldable phone is expected to cost as much as $1850.

The same report that suggests March as the release date says the foldable phone will cost as much as $1,770, although Samsung hasn't settled on the final price just yet. The firm plans to ship one million of the handset in 2019.

That's around £1400, but it's unlikely we'll pay that in the UK. Usually pound and dollar prices are more or less the same, so we could be looking at a smartphone that's just a couple hundred pounds cheaper than buying two iPhone Xs.

Galaxy X or Galaxy F?

It's widely thought that the upcoming foldable phone from Samsung will be the Galaxy X.

However, Twitter user @MMDDJ_, who has a good track record with phone leaks, suggests that it will actually be named the Galaxy F instead. 'F' for foldable?

What are the rumoured specifications for the Galaxy X/F?

The Samsung Galaxy X was originally rumoured to be a 5in phone that could fold out into an 8in tablet, but we now know it's a 7.3in panel called the Infinity Flex Display which is 4.6in when folded. As detailed at the top of the article, the device will use a new One UI to run three apps at once.

According to early rumours the screen resolution is expected to be 4K (3840x2160 pixels), ensuring that it remains high-res when folded.

Samsung Galaxy X unbreakable panel

A press release from Samsung touting an unbreakable panel could be used for the Galaxy X. Samsung Display has developed the "flexible OLED panel with an unbreakable substrate and an overlay window securely adhered to it".

The firm said that it will be used on smartphones along with "display consoles for automobiles, mobile military devices, portable game consoles and tablet PCs for e-learning".

The Galaxy X could also feature a dual-camera at the rear, one of the latest Qualcomm Snapdragon processors - most likely now the Snapdragon 845 or Exynos 9810. There should be a microSD card slot, but the battery will not be removable. 

Other specs are likely to follow that which we've seen in the recently announced Note 9, such as up to 512GB of storage, 8GB of RAM and an S Pen stylus with Bluetooth support. We could also see the same camera tech, a 12Mp dual-lens model with an AI Scene Optimiser mode and Flaw Detection.

It's thought that the Galaxy X won't be 5G compatible.

A patent application filed by Samsung in late 2016 shows some renders of what the eventual Galaxy X may look like (via Sammobile):

Galaxy X patent

What is a foldable phone?

A foldable phone is exactly as it sounds, one that either folds inward (like a clamshell phone) or outward and reveals a tablet-like device when stretched out. This is possible with the use of a bendable (rather than flexible, as seen in the Galaxy S7 edge) OLED panel.

Samsung, Lenovo and LG have each showed off bendable displays and devices at various industry events, and have registered many patents for the technology. Previously called Project Valley, Samsung’s technology has become known as the Samsung Galaxy X, which may or may not be its eventual name upon release.

Samsung originally worked on fold-in phones, which close up like a wallet, but having completed its work there it has moved on to fold-out phones. These should be more convenient for the user, who wouldn’t need to unfold the phone every time they wanted to use it.

Read next: Best new phones coming in 2018 and beyond

Follow Marie Black on Twitter.