Facebook is holding a special event at its Menlo Park headquarters on Tuesday, Jan. 15 and speculations regarding what the company will unveil at the event are gaining traction.

Facebook could bring a major overhaul to the social networking site. However, it would be a regular exercise rather than something big that the social giant is building, which adds fuel to the rumors that the spotlight of the Jan. 15 event will be on the long-rumored Facebook Phone.

According to TechCrunch columnist MG Siegler, Facebook will finally unveil its own smartphone, or, at least a kind of it, in the upcoming event.

"Multiple sources have told us that they expect some sort of Facebook Phone to be on display on Tuesday... It's not entirely clear if this will be an actual piece of Facebook branded hardware or if they will simply use hardware from a phone maker to show off some sort of new Facebook OS for mobile. That is to say, it could very well be that the "Facebook Phone" is more about a Facebook OS running on a phone," Siegler wrote.

The idea of Facebook Mobile dates back to 2011 and gained spotlight when AllThingsD reported on 'Project Buffy' in November 2011. The smartphone was reported 12 to 18 months away from launch, which fits perfectly with Q1 2013 release date.

Facebook CEO Mark Zuckerberg denied building a phone several times, but it is pretty common place for tech firms to deny rumors. Apple completely discarded the notion of a smaller iPad and Google denied working on a Google Phone. However, Google Nexus devices and iPad mini are presently key tech products in the market. Similarly, it is highly possible that Facebook may release its own phone on Jan. 15.

Even if the reports are true, it is still a big question about what OS will the phone run? In the smartphone market, dominated by Android and iOS, will the dedicated-social networking OS survive? Evidently, Facebook has been working hard on the software part.

Facebook has even built an App Store of its own. Facebook users can now send voicemail messages across the platform and the social giant is bringing VOIP calls feature in the near future. Facebook has already done a couple of things. However, according to Siegler, "the obvious answer would be a fork of Android", allowing "the OS to run hundreds of thousands of apps that are already out there."

Do you think Facebook is really going to launch a phone?