What did the British actor Christian Bale do to prepare for his role in the 2004 psychological thriller The Machinist?

Did you know Thespis, a Greek man, was the first actor in the world and he did his first act on November 23, 534 B.C.? Before that, people used to sing and dance, but they never portrayed a fictional role. It's because of Thespis that actors are also referred to as 'thespians. '