Forgetful Actor

An actor had been out of work for years because he always forgot his lines. One day he got a phone call from a director who wanted him for an important part in a play.
All the actor had to say was, “Hark! I hear the cannon roar!”
Opening night arrived, and while he waited in the wings, the actor muttered to himself, “Hark! I hear the cannon roar! Hark! I hear the cannon roar!”
The time for the entrance finally came. As the actor made his appearance onstage, he heard a loud BOOOOM! He turned around and said, “What the heck was that?”