When you're out exploring the Delta Quadrant, you want people around you who have been there before. It's a big, unfriendly place, after all. Star Trek Online
players will have a bit more help than they had previously expected, though. In addition to Tim Russ (Tuvok) and Garret Wang (Harry Kim) reprising their roles from Star Trek: Voyager, Ethan Phillips (Neelix), Jeri Ryan (Seven of Nine), and Robert Picardo (The Doctor) will be making appearances in the game.
No details on these appearances have yet been revealed, although Neelix is likely still in his role as ambassador, and the game's backstory has Seven of Nine working with the Daystrom Institute. It's likely that more lore will be uncovered as the expansion approaches its release this fall.
[Source: Cryptic Studios