(Pocket-lint) - Sony Mobile is expected to announce the successor to the Xperia XZ3 at Mobile World Congress, but the company may have just confirmed one of the main rumours flying around about the new flagship.

The Sony Xperia XZ4, as it is rumoured to be called, is claimed to be coming with a new aspect ratio of 21:9. Several leaks have suggested this ratio, presenting renders of the new device with a tall and slim form factor and a display to match.

Though nothing is yet official, a recent tweet from the Sony Xperia Twitter account suggests the rumour of the 21:9 aspect ratio may well be true. The tweet told us to "embrace a new perspective" and the accompanying video shows a wide cinema-like display.

Nothing else was detailed in the tweet, though it mentions Mobile World Congress and the time and date of the Sony press conference - 25 February 2019 at 07:45 GMT - suggesting it is talking about a smartphone.

While many of Sony's competitors offer an 18:9 or 19:9 aspect ratio on their smartphones, a 21:9 ratio would be a first in the smartphone world, so while 21:9 isn't mentioned in the tweet, it would support the "new perspective" idea. It's the aspect ratio you would watch films in at the cinema so to place it on a smartphone would presumably offer a more immersive experience when watching content.

We expect to find out more next week, but in the meantime, you can read our rumour round up on the Sony Xperia XZ4 to see what else the device is expected to come with. 

Writing by Britta O'Boyle.