Sony has already wowed the world with its Xperia X Performance smartphone which sports a 4K screen, yet it may already have an HDR upgrade. The Sony Xperia X Premium is being leaked as the world's first HDR smartphone which is set to be the brightest with most colours.

The Sony Xperia X Premium, according to sources of Phone Radar, is going to offer a 5.5-inch display at 1080p resolution which can manage High Dynamic Range. Baring in mind that televisions haven't had this feature for long that's an impressive jump, even if it isn't 4K also.

One of the important parts of HDR is brightness, in order to show that range. That's why the Xperia X Premium should come with a screen capable of up to 1300 nits of brightness. By comparison the Samsung Galaxy S7 tops out at 855 nits.

For colour depth this HDR screen will offer a staggering 1.07 billion where the nearest best right now manages just 16.8 million. So instead of 256 shades of RGB colour, the 10-bit HDR display manages 1024 colour shades.

On top of all that the screen refreshes at 120Hz and has a contrast ratio of 2000:1.

But what's it all for? The 4K Sony Xperia X Performance hasn't proven that useful or sold that well. But, in the near future, virtual reality will require these refresh rates and colour ranges as people start using their phones more in headsets. Looking at screens that close requires quality and, in order to avoid disorientation, a good refresh rate.

The Sony Xperia X Premium is expected to run a Snapdragon 820 processor with Adreno 530 GPU, 3GB of RAM and USB-C. When it will appear is not so clear.

READ: What is Ultra HD Premium and why does it matter?