By that point, I had started taking singing lessons. And after the first session, I mean, I was surprised that the windows didn't shatter. And after the third session, I really didn't know where this voice had come from.

In February 2012 Butler's publicist announced that Butler had completed a course of treatment for substance abuse of pain killers at a rehab-centre. Despite the film receiving mixed reviews Butler was praised for his performance. It’s the work and not the adulation that has proved to be the most fulfilling.

In 2007 Butler gained recognition through his portrayal of King Leonidas in the film 300. S. He also appeared as a voice actor in How to Train Your Dragon (2010).