Dwayne Johnson is soon heading to theaters in what might be the most dramatic role of his career so far. In "The Smashing Machine," Johnson will play MMA and UFC fighter Mark Kerr, who was the subject of a 2002 HBO documentary that chronicled his substance abuse and explored the brutality of the sport to which he'd dedicated his life.

Dwayne Johnson stars as former wrestler and UFC star Mark Kerr in a new trailer for Benny Safdie's "The Smashing Machine."

The first trailer for The Smashing Machine has arrived, and it's a gritty look at a UFC champ. In the footage, which you can watch above, Dwayne Johnson looks unrecognizable as MMA fighter and two-time UFC Heavyweight Tournament Champion Mark Kerr.