It seems that The Twilight Saga: Breaking Dawn is already pretty far into pre-production, as Chaske Spencer revealed on Twitter (spotted by BreakingDawnMovie) that he’s been training since last Tuesday:
training day 3 – the saga continues
pretty sore after training yesterday
Of course, he could just be hitting the gym on his own, but — well, it’s hard to complain about that. 
August 23, 2010