1) Chew the scenery 2) Emote 3) Ham 4) Ham it up 5) Overplay 1) Chew the scenery, so to speak 2) Emote 3) Emulate a ham 4) Exaggerate, on stage 5) Ham it up 6) Make too dramatic 7) Overplay 8) Play 9) Play to the gallery 10) Playact 11) Risk a bad review 12) Roleplay 13) Wrongly take center stage 
• (v. t.) To act upon, or influence, unduly. • (v. t.) To act or perform to excess; to exaggerate in acting; as, he overacted his part. • (v. i.) To act more than is necessary; to go to excess in action.
O`ver·act' intransitive verb To act more than is necessary; to go to excess in action. B. Jonson. O`ver·act' transitive verb 1. To act or perform to excess; to exaggerate in acting; as, he overacted his part. 2. To act upon, or influence, unduly. [ Obsolete] « The hope of inheritance overacts them.» Milton. 
[v] - exaggerate one`s acting
to act in an exaggerated manner.