Mad Men star and recent 30 Rock guest Jon Hamm has joined the cast of Howl, the adaptation of the story behind Allen Ginsberg’s famed poem, according to Variety. The film is currently shooting with James Franco as Ginsberg and Jeff Daniels, Mary Louise-Parker, and David Strathairn in supporting roles. Hamm will play Jake Ehrlich, the defense attorney in the obscenity trial provoked by the explicit nature of Ginsberg’s collection of poems. (Ehrlich, incidentally, was also the real-life inspiration behind TV’s Perry Mason.) The film is one of two Ginsberg projects in development — the second being Kill Your Darlings, with Adventureland star Jesse Eisenberg playing the iconic poet.