SWTOR's Deceived trailer, there was an odd shot of the Jedi leader giving a signal to an astromech droid. Per usual, the writers at BioWare do not put anything into their trailers without a specific reason. This past Friday, that little droid was revealed to be a companion for the Jedi knight class, named T7-O1 (tee seven - oh one). This little bot calls back to both T3-M4 of Knights of the Old Republic and, of course, R2-D2 of the Star Wars movies. In fact, his attitude is very similar to R2-D2's. According to the companion page on SWTOR's official site, he considers his owners to be more like partners and less like masters.
T7-O1 was activated over two centuries before the Treaty of Coruscant and has yet to be memory-wiped in that whole time. He remembers every organic he has ever worked with, from the petty smugglers, to Senator Oodora of Manaan, to Captain Nico Okarr, and to Jedi Master Ven Zallow, whom we witnessed being killed by Darth Malgus in the previously mentioned trailer. For your Jedi knight character, you can expect this droid to be an invaluable source of information. His surveillance, cartography, and data-slicing skills are unmatched.
BioWare has not revealed where your Jedi knight will meet T7-O1, just like every other companion mentioned for this game, but rest assured, he's waiting for you somewhere in that galaxy far, far away.