Starring along side Robert Downey won't be a first either, back in 1987 Spader and Downey shared the big screen in Less Than Zero.
Its unknown if Spader will do anything other than lending his voice for this role, but my suspicions would make me believe he'd want to do the motion capture as well. whatever happens, stay tuned for all updates from Marvel Mouth, one thing is for sure, Loki approves:
Go on, James Spader. Go get 'em. @Avengers #AgeOfUltron
— Tom Hiddleston (@twhiddleston) August 29, 2013