Sony says the Xperia Z Ultra is the world's slimmest smartphone with a full HD display.
The device is yet another Android phone that blurs the line between a phone and a tablet.
At almost 180mm tall and over 92mm wide, it will immediately become one of the largest smartphones on the market, though it's only 6.5mm thick.
The size is comparable to Samsung's Galaxy Mega 6.3, so it's much larger than the Samsung Galaxy Note II, and even the 6.1in Huawei Ascend Mate.
Sony has followed a similar design to its Xperia Z smartphone. It has a long rectangle shape with flat sides, square corners and a sheet of tempered glass on both the front and the back
The Xperia Z Ultra weighs 212g, which is heavier than the Galaxy Mega 6.3. It's also waterproof, not just water resistant.
The phone has a 6.4in, full HD "Triluminos" display which is Sony's fancy marketing term for a new technology that claims to display a wider palette of colours.
The Xperia Z Ultra is powered Qualcomm's new 2.2GHz, quad-core Snapdragon 800 processor, has 2GB of RAM, and includes 16GB of internal memory.
A microSD card slot handles extra storage, while the phone is also 4G capable and will therefore work on all Australian networks.
The Xperia Z Ultra comes with a stylus that allows users to write and sketch on the screen. However, Sony says the handwriting recognition feature will work with any regular pencil or pen, provided the tip diameter is over 1mm.
An 8-megapixel rear facing camera with Sony's Exmor RS sensor is on the back, but there's no LED flash.
The phone's waterproof capabilities means you can film full HD videos underwater. A front-facing 2-megapixel camera handles video calls.
Other features include a large 3050mAh battery and NFC-connectivity, though the battery is not removable.
The Xperia Z Ultra comes with Google's latest Android 4.2 Jelly Bean software and will be available in black, white, and purple colour variants.
Sony says the phone will launch globally from Q3 2013, but the company has already confirmed the device will officially be released in Australia later this year.