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

Dwayne "The Rock" Johnson transforms into MMA and UFC fighter Mark Kerr in Benny Safdie's A24 biopic "The Smashing Machine," releasing this fall.

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.