Who plays the soldier (the real Harry Angel) in Times Square?

So: Johnny Favourite (Rourke), Margaret (Rampling), Toots (McGhee) and Ethan (Fontelieu) on New Year's Eve, 1943 go to Times Square and pick a soldier apparently as old as Favourite in order to steal his soul in a murderous ritual and fool the devil. The soldier's name is Harry Angel. All of that is shown in flashbacks.
My question is: who plays the part of the soldier in Times Square? Was he just an extra?