Julian Bleach (the Nightmare Man) played the similar Ghostmaker in From Out of the Rain (2008). He also played the recurring role of Davros in Doctor Who (2005), placing him among a small handful of actors who were in all three branches of the Whoniverse during the Russell T. Davies era.
The song playing during the party scene is Untouchable by Girls Aloud. It can be found on their 2008 album Out Of Control.
Julian Bleach's performance as the Nightmare Man appears to be based in part on Batman's arch nemesis, The Joker.