An invitation to the French launch of a new Sony Mobile device has given us a better idea of what the company's rumoured phablet, the Sony Xperia Z Ultra, might look like.

The side-shot of the new device on the invitation seems to mirror Sony Mobile's current design language. The central power/standby button, as well as the volume rocker beneath it, reflect the Xperia Z and Xperia Tablet Z devices already available.

READ: Sony Xperia Z review

Rumours of a larger Sony Xperia device have been circulating for some time. Going under the name of Sony Xperia ZU, or Z Ultra, it is reported to offer a 6.4-inch 1080p display, and run on the new Qualcomm Snapdragon 800 processor.

Although this invitation is for an event on 4 July, we strongly believe that we'll see its announcement on 25 June.

The invitation wording also hints at the type of device this is going to be, saying there's a "big surprise" and that you should remember to put a "note" in your agenda, the latter part handwritten by a pen.

This tallies with Sony's phablet being a competitor for the likes of the Samsung Galaxy Note range, a market that's attracting plenty of attention. Launching into this space recently we've seen Acer with the Liquid S1 and there are rumours of the HTC One Max, a larger Sense-packing phablet.

We'll be watching Sony, so stay tuned for the big announcement when it happens.