The pretty reliable @evleaks Twitter account has what it claims are specs for the device, rumoured to be called the HTC Myst. It's a mid-range affair, if these are anything to go by, but it will come with Android 4.1.2 Jelly Bean on board, for all your Google Now needs.
The Myst is quite small by today's standards, sporting a 4.3-inch, 1,280x720-pixel resolution screen, with a pixel-per-inch count of 320ppi. It'll have a 5-megapixel camera on the back, a 1.6-megapixel front-facer, with a dual-core 1.5GHz processor inside, 1GB of RAM, and 16GB of storage, with no microSD card slot. It'll be 4G, too.
Sadly there are no more details on what exactly make it a Facebook phone, but expect a host of preloaded social networking goodies. Facebook could also be baked into the operating system, though I'm not sure how that would work alongside HTC's own Sense UI. HTC has just unveiled the latest version, Sense 5, on the HTC One, and has announced it'll bring it to older phones too, so there's a chance it won't want to share the software limelight with any fancy social networks.
HTC has a track record of nearly every one of its devices being leaked. Last week, we heard news of a device called the HTC Tiara, another mid-range effort, but this one running Windows Phone 8. It's rumoured to be the first handset to run Windows Phone 8 GDR2, which is the second update to the operating system since its debut at the end of last year. The specs look slightly lower than the Myst, with a lower resolution screen, too.
Do you 'like' the sound of a Facebook phone? Let me know in the comments, or on our Facebook page.