THR says twice-times over Oscar winner Kevin Spacey has joined the cast of Horrible Bosses.The dark comedy (directed by Seth Gordon) centers on three pals who plot to kill one another's pain-in-the-ass bosses. Quitting and looking for better work wasn't an alternative? Jason Bateman, Charlie Day and Jason Sudiekis headline as the homicidal BFFs.The one-time Lex Luthor will play Bateman's boss described as "a master manipulator with an attractive wife." Jennifer Aniston and Colin Farrell are the other two bosses in question and Jamie Foxx will play a scam artist.Production is expected to start on July 6th.