Ben Cotton (The Killing, Hellcats) will take on the role of Tweedle Dum
Matty Finochio (50/50) will be playing Tweedle Dee.
How the two playful & jolly brothers will fit into the story is unknown at this time.
Ben Cotton was most recently seen as "Pastor Mike" in the AMC crime-drama "The Killing"
Matty Finochio was most recently seen in "Supernatural" season 8 episode of "Freaks & Geeks"
The pair worked together in the past on a film "Doppleganger Paul"
UPDATE August 19, 2013
Ben Cotton (Tweedle Dum) confirms the casting of him & Matty Finochio in front of a live audience at an event for Project Limelight at the East Of Main Café tonight.