...his hair, that is. The actor recently shaved his trademark scruffy locks (and beard!) for his role in the film End of Watch. This isn't the first time Gyllenhaal has cut it all off -- he went bald for the first time in April.
Nor is he the first star to take such a drastic step for a role. From Demi Moore to Zach Galifianakis, actors, it seems, will do anything for their craft. Check out our gallery of stars who bared all -- of their scalp -- for a film: