Ham

Histrionics
1. Behavior or speech for effect, as insincere or exaggerated expression of an emotion. 2. Dramatic representation; theatricals; acting.
"celeb magazines are nothing but histrionic junk and pointless gossip"
No, this post is not about the meat that is a cut of pork and is often served with cow mold (cheese) and yeast grass (bread). What I'm talking about is the type of actor as seen here:
http://en.m.wikipedia.org/wiki/William_Shatner
A ham actor is someone who overreacts to everything, While they're acting at least. Ham actors are often found amongst amateur and understudies (if you don't know what that is, then look it up), due mainly to the fact that they get very little stage time. And I know that everybody knows someone who is a ham actor, so the next time you see yours, acl them for me. Thanks!