Bruce Willis wasn't expecting 'Looper' to be so ''emotional''.

The 57-year-old star plays retired assassin Joe, who travels back in time to hunt down a gangster, in the new film and while he stayed detached from the violence during filming, the actor wasn't prepared for his reaction when he watched the finished movie.

He said: ''When I was shooting the film I didn't think I was doing anything wrong as a character. I took it for granted that Joe would hurt people. I didn't judge him.

''But when I saw the film I was emotionally moved by how horribly wrong the things I was doing were. It is an emotional film. I wasn't expecting that.''

Joseph Gordon-Levitt stars as a younger version of Bruce in the film and the older star admits it was ''really strange'' seeing his co-star in full prosthetics.

He added to the Daily Star newspaper: ''I was sitting across from Joseph at a table. I was supposed to act and get my lines right but I just found myself looking at him and thinking how weird it was.

''It's really a strange thing to see someone who looks like a young version of yourself.''