Evidence is mounting that Sony is at least looking into the possibility of adding cell phone functionality to the PlayStation Portable, or adding PlayStation-branded content to other cell phones.

The first clue came last week when Sony Computer Entertainment corporate executive Izumi Kawanishi admitted in an interview with Japan's Nikkei BP (translated by IGN) that using the PSP as a cell phone was "a possibility" that he is personally interested in. Of course this idle chatter is far from anything official, but the idea seems like a natural progression for a system that will soon be able to do everything from playing movies to taking photos.

Then, early this week, CNet Asia noticed that Sony Ericsson Senior VP Rikko Sakaguchi mentioned at a conference that the company "is working on something" with regards to a PlayStation phone, but that "the surprise must be kept for the future." Again, nothing even close to official, but considering that classic Playstation games will soon be downloadable to the PSP, could cell phone emulation be in the cards as well?

(Pictured: an existing skin for the i330 cell phone, not meant to represent any sort of actual Playstation phone)

Read -- Kawanishi interview on IGN
Read -- CNet Asia Blog post