We’ve recently been drawn to this impressive post at the SuperHeroHype forums by ChicageauxTiger:

This was the general scene of the shoot:

Continue reading for the spoilers.

It turns out that a number of the big-wig movie characters were there, in force. First up, we have Aaron Eckhart - or Harvey Dent:

Second is Anthony Michael Hall:

Gary Oldman:

…and, rather importantly, Heath Ledger - not donned up in full Joker details, but still sporting a scar: