chew on the scenery

To be exaggeratedly or flamboyantly melodramatic or overly emotional while acting a role, as for television, theater, or film. I hated working with him on that play—every night he'd go out and chew on the scenery so much that he was the only one the audience noticed! I love watching hammy actors chew on the scenery in bad movies. This part requires an understated performance, so tell the casting director I don't want anyone who's gonna chew on the scenery.