North Pole-aris said:
Very few comic actors have taken on dramatic roles and embarrassed themselves; the reverse cannot be said.
You're right. Robin Williams, Will Smith, Jim Carrey, even Adam Sandler have taken on great dramatic roles.
Contrast this with say, Christopher Walken, known for his tough guy roles, who recently has been appearing in strange , some might say misguided, comic roles, like 'Wedding Crashers', 'Old School', 'Click' etc.