Dubbed Phone, the app “shows you info about who’s calling and automatically blocks calls from commonly blocked numbers,” according to a message that Facebook is sending to select users.
The experimental program -- first reported by AndroidPolice, on Friday -- complements Facebook’s aggressive push into mobile.
The number of mobile Facebook users worldwide will approach 1 billion this year, eMarketer estimates. Put another way, more than 70% of all Facebook users will use mobile this year. By 2018, more than three-quarters of the social network's audience will access it via mobile phones on a regular basis -- reaching 1.34 billion users.
Stateside, nearly 80% of Facebook users -- or 123.1 million consumers -- are expected to access the site regularly via mobile device this year, per eMarketer. Overall, Facebook’s share of the $36.5 billion worldwide mobile ad spending is expected to reach 20.4%, this year, according to eMarketer.
Separate and apart from Facebook proper, the company's WhatsApp unit claimed more than 700 million monthly active users, in January.
At the end of January, Facebook boasted 1.4 billion users worldwide. On mobile, Facebook saw an average of 745 million daily active users in December -- an increase of 34% year-over-year -- and 1.19 billion monthly active users, which was up 26% year-over-year.
Facebook declined to comment on the existence of the app on Monday.